Unintuitive yes, and I'm not going to disagree with you on UX, but it's not a particularly difficult thing to learn if you use a rebase centric workflow and this is a command I use daily.
P.S. don't forget to use --update-refs (or add to your .gitconfig) ;-)
> It’s trivial to separate that result into two or more steps
Okay first, tell me how to separate it into two or more steps. Second, tell me why a single operation in a user’s mental model needs to be split into two commands. The user is thinking about moving a commit and its descendants from one place to another; why should this seemingly atomic operation be split.