Cloud is great for when you want to rent someone else’s computer space. It can be cheaper than building a data center, maintaining the hardware and software, expand and contract dynamically.

For example a ton of servers can be brought online for something like if Netflix was streaming the super bowl. They might suddenly need 3 times the servers they normally need, cloud is good for that sudden expansion, but tends to be more costly for regular use.

Super computers are great for lots of calculations very quickly. For example you want to simulate the air flow of individual air molecules over a new airplane wing design. Or some other kind of complex mathematical modeling in science, or finance.