I (and I suspect most others) must have SMS for two-factor auth. There are many sites that require it, or that send texts as their only login mechanism. I personally use my phone pretty often. Making doctors appointments, coordinating with friends while on trips, or calling just to talk.

I recognize that Signals, WhatsApp, etc. are what most people want, but I personally want to unplug from social media, so not having those apps is fine for me.