It's common in general open source projects where you might want to send a patch for something that you don't have commit priveleges too, but I've never seen that used in enterprises as they have central auth / groups with the users required to work on the code.

I don't think that's a common workflow within companies. In every org I have worked at, forking is explicitly disabled

I worked at a large gaming company and that was definitely the collaboration model.

Before per-branch controls, the only way to disable write access (while maintaining read access, pull-request privs, etc) to a repository's blessed branches was forks.

You don't have 500000 garbage leftover branches on the main repo.