Why Companies Use the Cloud
😟 THE PROBLEM
A shop’s website goes down on its busiest sale day, and customers leave.
😊 THE SOLUTION
Move to the cloud: capacity grows in minutes and costs follow demand.
- IT projects wait weeks for hardware✓ Start building the same day
- Traffic spikes crash the site✓ Scale up for the rush, down afterwards
- Engineers spend days fixing servers✓ The provider runs the hardware
Quick answer
Companies use the cloud to move faster, spend smarter and scale without limits. They avoid big up-front hardware purchases, get capacity in minutes, scale up and down with demand, reach users worldwide, and inherit the provider's investment in reliability and security, so their own teams can focus on the product.
Exam objective: 1.1.1 Define cloud computing. 1.2.1 Describe the benefits of high availability and scalability in the cloud. (Skills measured as of July 20, 2026)
Start with a question
Your online shop gets featured on national TV tonight. Can your website handle 50 times the normal traffic by 8 pm?
If your website runs on two servers in an office cupboard, the honest answer is no. Ordering more servers takes weeks. By the time they arrive, the TV moment is over and those customers have gone elsewhere.
That single story contains most of the reasons companies move to the cloud: speed, scale, cost and not losing customers.
Explain it like I’m 10
The technical explanation
The business case for cloud usually rests on six benefits. Each one gets its own lesson later, so here is the map:
| Benefit | The business problem it solves | Covered in |
|---|---|---|
| Cost efficiency | Large up-front hardware spend, paying for idle capacity | Consumption-based model, CapEx vs OpEx |
| Speed and agility | Weeks of procurement before any project can start | This lesson |
| Scalability and elasticity | Traffic spikes, growth, seasonal demand | Scalability, Elasticity |
| Availability and reliability | Downtime when hardware or a datacenter fails | High Availability, Reliability |
| Security and governance | Keeping up with threats and compliance rules | Security, Governance |
| Manageability | Too much manual operational work | Manageability |
Speed is often the hidden winner
Cost gets the headlines, but many organisations say agility is the bigger prize. When a developer can create a test environment in five minutes and delete it at lunchtime, the whole organisation experiments more. Ideas that would never justify a hardware purchase can be tried for the price of a coffee.
Economies of scale
Microsoft buys servers, electricity and network capacity at a scale no single company can match. It passes part of that saving on, which is why compute and storage unit prices tend to fall over time.
Focus on what makes you different
A bank’s customers do not care who replaced a failed disk last night. They care about the banking app. Every hour engineers spend on undifferentiated heavy lifting, such as racking servers or patching firmware, is an hour not spent on the product.
Real-world business scenario
A mid-size retail chain going online
- The problem
- Its own datacenter was near capacity, the next hardware refresh would cost millions, and festive-season sales crashed the site two years running.
- What they used
- Moved the web shop to Azure App Service with autoscale, product images to Blob Storage with a CDN, and the order database to Azure SQL Database.
- Why that choice
- Avoid the hardware refresh (CapEx), absorb festive peaks automatically, and free the infrastructure team to work on omnichannel features.
- The result
- The festive season ran without outages, the datacenter contract was reduced, and new features shipped monthly instead of quarterly.
Visual: from idea to production
Traditional IT
- Write a business case
- Approve the hardware budget
- Order and wait for delivery (weeks)
- Rack, cable, install, configure
- Finally start building
Cloud
- Pick a service in the portal or code
- Resources ready in minutes
- Start building the same day
- Delete it if the idea fails
- Pay only for the time used
When to use it and when not to
✓ Use it when…
- You need to launch, test or expand quickly.
- Demand varies by hour, season or event.
- A hardware refresh or datacenter lease renewal is coming up. This is a natural moment to move.
- You want access to services you could not easily build yourself (global networks, AI, managed databases).
✕ Think twice when…
- Regulation or contracts require on-premises hosting.
- The workload is stable, already paid for, and works well where it is. Moving it may add cost without benefit.
- There is no plan for skills, cost control and security in the cloud yet.
↔ Alternatives to consider
- Move gradually with a **hybrid** approach: new apps in the cloud, legacy systems on-premises.
- Use **SaaS** products where they meet the need, and do not build at all.
Interview preparation
Say your answer out loud first, then open the model answer. Interviewers care more about your reasoning than the exact words.
Beginner Give me three reasons a company would move to the cloud.
Model answer
First, cost. No big up-front hardware purchase, and you pay for what you use. Second, speed. Servers are ready in minutes instead of weeks. Third, scale. You can handle traffic spikes and expand to new countries without building datacenters.
Interviewer follows up
Is there any downside?
You
Yes. Costs can grow if nobody manages them, you depend on the provider and your internet connectivity, and you still own security for your data and identities. Moving also takes effort and new skills.
Intermediate How would you explain the business value of cloud to a non-technical manager?
Model answer
I would avoid jargon and talk about outcomes. We can launch new ideas in days, we stop paying for idle servers, the website stays up on our busiest days, and our engineers work on features customers see instead of maintaining hardware. Then I would back it with numbers from a pilot or a TCO comparison.
Experienced developer What are the common reasons cloud migrations fail to deliver the expected savings?
Model answer
Lift-and-shift without right-sizing, so oversized VMs run 24/7. No tagging or ownership, so nobody is accountable for spend. Ignoring reservations and savings plans for steady workloads. Data egress and cross-region traffic left out of estimates. Keeping old operating models such as manual change tickets, so the agility gains never appear. FinOps practices and architecture changes towards managed services and autoscaling are what unlock the value.
Scenario A hospital wants to analyse ten years of anonymised scans with AI but has no GPU servers. What does the cloud offer?
Model answer
They can rent GPU capacity only for the weeks the analysis runs, use managed AI services, and store data in a region that meets healthcare compliance requirements. Buying GPU servers for a one-off project would be slow and expensive, and the hardware would sit idle afterwards.
Test yourself with exercises
4 original practice questions in the AZ-900 style. Pick your answers, then check them. You will see why each option is right or wrong. Score 75% or more and this topic is marked complete.
Quick revision
Key points
- Speed and agility: resources in minutes, faster time to market.
- Cost: no up-front CapEx, pay for consumption, economies of scale.
- Scale: grow or shrink with demand, globally.
- Reliability and security: inherit the provider's redundancy and security investment.
- Focus: stop doing undifferentiated heavy lifting and build what customers value.
Important terminology
- Agility
- The ability to try, launch and change things quickly because resources are available in minutes.
- Time to market
- How long it takes to get a new product or feature in front of customers.
- Economies of scale
- Large providers buy hardware and power so cheaply that they can offer lower unit costs than one company could achieve.
- Undifferentiated heavy lifting
- Work that is necessary but does not make your product special, such as racking servers or patching hardware.
Common mistakes
- Saying cloud is always cheaper. It is cheaper when managed well and used appropriately.
- Forgetting that the customer still has security responsibilities in the cloud.
Exam tips
- The exam names benefits precisely. Learn the difference between scalability, elasticity, availability and reliability in the following lessons.
- "No need to buy hardware up front" usually maps to OpEx / consumption-based model.
Five quick revision questions
-
1.What does "time to market" mean?Show
How long it takes to get a product or feature to customers.
-
2.Why can large cloud providers offer low prices?Show
Economies of scale, because they buy hardware, power and bandwidth in huge volumes.
-
3.Name one risk of moving to the cloud.Show
Uncontrolled costs, provider dependency, or new skills required.
-
4.What is undifferentiated heavy lifting?Show
Necessary infrastructure work, like patching hardware, that does not make your product better.
-
5.Which benefit lets you reach users in other countries quickly?Show
Global reach, by deploying to cloud regions near those users.
Official references
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