I tried it like a year ago, maybe more, and it wasn’t ready for that. The battery life was awfull (which was a SW issue of the OS not being able to stand-by properly), and accepting calls wasn’t really reliable. It’s more of a gimmick and great as a side-phone, but I wouldn’t use it as a daily driver.
But the situation might’ve changed.
I’ve seen this warning in a lot of apps, like Teams, Messenger or some authenticators, and some of the time I could simply ignore it and continue using the app. I think some of apps simply use it for push notifications that I can get by without.
Not all, though. Sometimes it simply doesn’t work.