Not everyone stays a beginner forever, and it's nice to have a tool that doesn't play to the
lowest common denominator. It's really not that hard to just do a "git commit -a" if you
want to avoid staging.
99% of developers out there didn't need a power tool for source control (source control is already quite a power tool many devs can barely handle, even in SVN form...), yet here we are: Git is imposed everywhere, with its horrible UX.
Git's UX isn't that bad if you're only cloning projects to build them locally and keep them updated.
The UX only gets really crufty as you use more and more of the features.