So what you say isn't really true. I would improve it to say that the existing terminology doesn't appear logical until you have learned about those basics. This is not the fault of git: any system becomes incomprehensible if you approach it with concepts in your head that are incompatible with that system.

A complete beginner may not want to start out by learning those internals, and that's okay. But at some point, it definitely becomes a worthy investment to take the mere hour or two that it takes to read through the relevant parts of the documentation.

Not wanting to argue which perspective is right, just that you can't make a broad sweeping statement that Mercurial has a better interface

At least (in trying to match what the GitHub applications do) it's not trying to invent a completely new system. But I don't see this getting much traction unless GitHub adopts it and pushes it as their "official" command line client.