The "copy as curl" feature is very useful when doing penetration testing of a web app, because you can quickly iterate on what requests you're sending. It also helps to download large files if, like me, you don't trust browsers to download your files properly (or if you want to download something from a server).

APIs aren't the only thing HTTP is used for. Although, you could stick curl commands in shell scripts as well to have dumb API scripts.

There are use cases for every feature.