I read somewhere that being the only kid without smartphone access is worse (for mental health) than giving your kid a smartphone.

I.e. there needs to be consensus among parents.

I suppose that is because of social exclusion. If all the important things are coordinates online and in real-time, then those kids can't participate. Communicating with your peers is much harder when the peer's baseline is "I'll just write a chat message" and it would take considerably more effort to talk to the kid who doesn't have mobile internet access.

Perhaps what relate the study kids was their school, which is probably already existing I guess ?

> I read somewhere that being the only kid without smartphone access is worse (for mental health) than giving your kid a smartphone.

What is definition of worse in context of mental health? Can free and open-source devices help or proprietary software is inevitable?