This is superficially true but fundamentally incorrect. There is one Git mode that everyone uses: Magit. Magit is incredible; it is one of a couple Emacs integrations that make the tool it integrates with better, in a significant and meaningful way.
I'm not a "use Emacs as my shell", "read my email in Emacs" kind of person. And I am nowhere nearly as effective in Git on the commandline as I am with Magit.
Use Magit.