Agreed - texting should absolutely be banned in the classroom.
But I think that could easily be controlled by the teacher in the classroom vs an outright ban on smartwatches which have increasingly health related uses.
In some cases a student is going to need their smartphone as well for health purposes (Eg diabetics who monitor their blood sugar via their phone)
But otherwise, yeah, ban away.
Blood sugar can be monitored by the nurse.
Classrooms are a zoo now. I am not that old. But a couple decades ago, my school banned "beepers". Yeah it's an ancient device. But their explanation was that usually the beeper would prompt you too get in touch with your "dealer" so that why they were banned on campus. Anyone with a beeper will get a suspension.