Why not? If they are not old enough to drive or go places on their own the phone is probably the main way they communicate outside of school. My family does hand me down phones for kids and I could imagine having compatibility issues like old android vs new iPhone can’t video chat easily or whatever.

I’m not saying this is for sure the case, but I can envision a world where having compatible phones makes some things easier. It is surely not as bad as the good old days when some people had flip phones and some had smart phones. But there still may well be a gap.