Yes because we collaborate using it. Its certainly easier then understanding the js this pointer.
If you use SVN, CVS or mercurial on a regular basis in your projects then you will probably need to use git in the future and the answer will be yes. If version control is not something you handle then the answer is no.
Do you think that there's really space nowadays for someone who works with files containing any kind of code (ui, markup, program, ...) and doesn't use a VCS? I find it really hard to find people like that and working with them is rather painful (they will end up in a position where they just have to know git, or someone will have to do their work for them).
I would say you don't need to know the minutiae, but having at least a basic understanding will be very helpful.
yes! not only will it add value to yourself, a day will come on which you will need it so badly that you'll hit yourself in the foot with a shovel for not having learned it!