That's a convenient generator for pull requests, sure, but a pull request is still a human mechanism, not a git mechanism. The "pull request" itself is still just a message requesting a pull, not some concept that git (either the commands or on-disk representation) is specifically aware of.

To that point, GitHub still does not use git-request-pull or even pulls to implement PRs, so the name is still not correct there. GitLab's naming is more accurate.

You just linked a shell script that writes an email.

It came first, but what GitHub called "pull requests" is very unlike what git does here. Even Torvalds famously ranted about that.

"Merge request" is a much better name for what GitHub actually does.