Fugitive is hugely useful and actually provides features above and beyond tig.
That said, tig has an innate simplicity that works for people who are not native vim-ers.
I primarily use screen windows for different functionality. While I can accomplish everything from vim-fugitive, I still maintain a "git" window purely for mind-segmentation and window-SRP reasons.
Thus, tig may open up a completely new concept of active git interfacing.
That said, it is yet another keystroke set to remember (albeit a small keyset).
Thanks apple, for dashing the hopes and dreams of this twenty-something, now bawling their eyes out and screaming for Frozen.