This is kind of a strange bar to set. There are entire companies that don't use git. In fact, most projects hosted on Google Code (now defunct) were using Mercurial.
If you've not used Git or GitHub or any of the cloud providers for Git, it's a signal. To me it signals that someone uses open-source software or has some passing familiarity with it.
As a person that conducts interviews, the things that people leave public on a GitHub profile have been a pretty invaluable signal of attention to detail or code quality. If I see someone with a dotfiles repository, it likely means that they care about their craft a bit, and it factors into a part of the whole evaluation pie.