This seems to be a large difference in people's work flows. Some of us like to remember things like what branch we're in, the file system structure of our project so we can edit in vim without needing NERDtree or some other IDE that organizes stuff, we like to know our libraries so we don't need auto-completion, and then there's the opposite people. For myself, I think the remember-for-me tools have their place, and I'm a fan of Flex's Flash Builder IDE even though I use vim for everything else, so I won't begrudge someone for choosing not to remember something. That's what doc is for.
On the other hand, in this case I frequently just use 'git status' which reports my branch anyway among other info I want to double-check just in case I somehow forgot, and this is really just a neat shell trick rather than being really useful, like the one that prints a green ':)' when the last command succeeded and a red ':(' when it failed...
It seems a lot simpler to just type "git br" (or, heck, "gb") when I care. Usually I have a good reason for being in a particular branch, though I tend to check before doing merging anyway.
When I want to fiddle with minor configuration details, hey, bash and zsh users have nothing on emacs. ;)
