We have implemented in our systems we develop. One key thing, however, we have run into is consumer education with support for 2FA and how to use. For all of us tech types its really important. For average joe, which surprises the heck out of me, is confused by it if not annoyed by it.
LOL, our lead developer gets annoyed everytime he hits AWS console and has to dig out his phone. We love that sideshow.
I expect adoption to grow even among the non-tech savvy over time…
As a user, I use everywhere I can…especially like Authy.