"I'm in a terminal or, most likely, my editor way more often than I'm in the browser and for any non-trivial change it's way faster to use git in the terminal or fugitive (vim-git integration) than the web interface."
I've no doubt that this is true for you, but other users have very different situations.
I'm a front-end developer, which means that I live in the browser. For me, if it's just a simple change, I'd much rather do it from the browser than the terminal. This is despite the fact that I know the terminal pretty well (love tmux and tmuxinator, for example).
Oh yeah, I have no doubt that's true for a lot of people but as far as I know you folks are still a small minority.
Even when I'm doing CSS and I spend a lot of time in firebug/dev tools that's just for experimentation, the first step before interacting with git is still changing some file which I do in an editor. Although I also use a lot of "live preview triggered on save" type workflows rather than building stuff in the browser which I know is unusual (not for long I'm guessing).
I've no doubt that this is true for you, but other users have very different situations.
I'm a front-end developer, which means that I live in the browser. For me, if it's just a simple change, I'd much rather do it from the browser than the terminal. This is despite the fact that I know the terminal pretty well (love tmux and tmuxinator, for example).