When all your services and resources reside on the cloud, there is no need to maintain huge data centers (plus no more power bills! ).
You also don’t have to hire a large IT team to take care of infrastructure set up or taking care of the security, all of this will be handled within the cloud.
So when you start building your infrastructure, you can choose resources based on your business needs like the OS you want to set up, the network capabilities, the storage size etc.
Let’s consider any ecommerce website, during the holiday season, they expect a lot of traffic to their website so they can scale up and add resources to handle the additional traffic.