Re: 2FA
In a lot of cases SMS just doesn't work. Both my smart phone and my smarter simple phone lose them regularly in the bowels of the phone... and the last time I looked, SMS delivery was not guaranteed.
Furthermore, some of us regularly misplace our smartphones for up to a month or two at a time, which makes them useless for any type of priority communication. I've never had it hide for more than six or seven consecutive months, but I really don't know what happens to SMS messages when it's been powered off for that long.