For example, some people don’t like that it’s centralized. It’s not like e-mail, where you can register with any provider and then cross-communicate. Moxie wrote more about this here

I switched to a feature phone that has nothing to do with Android for calling (Mocor RTOS aka S30+) because I’m tired of fighting Android for the moment. I keep an unrooted smartphone at home for online banking. Kinda extreme but that’s one way.