Comment by monsieurbanana

My bad, I didn't knew you wanted a serious answer, I should have known that some people would seriously consider having three separate phones for texting, calling and everything else.

For a serious answer then: Rather than segregating phone calling vs the rest, if you want to go to the hassle of maintaining multiple phones, I would put sensitive apps (i.e. bank apps) separated from the rest.

But ultimately it depends on which threat model you are trying to mitigate. Most people would worry about protecting their financial information. If you are worried about possible backslash from a fascist state, you shouldn't use normal phone calls at all and switch to a privacy app.

OTOH, a dedicated phone just to make phone calls makes sense if your threat model is your significant other.