This doesn't really help for anything except for content editing (e.g., markdown). Consider the above example: the original poster now has all these files they've changed on disk. The best case scenario now involves opening all those files up one by one and pasting them into the browser's textarea. (Can you change multiple files this way and wrap it up into a single atomic commit? Whatever the case, this actually results in a lot more pointy-clicky, not less.)
A patch is a unit of change. Historically, that's the type of unit that the open source world has operated with. The only reason we're having this conversation right now is because GitHub decided to build on top of pull requests instead of patches for lock-in reasons. GitLab has no such motivations, so it's silly to continue following them, especially since Git has had native support for patches from the beginning.
Just support patches already.