Surface level I agreed but thinking more on it I don’t.
Emergencies and early pickups should be the responsibility of the adults i.e. teachers and administrative staff. They are responsible for you while in school so they need to be informed either way.
Late pickups can be discovered when the school day is over and they get their phone back / access to it.
Learning tool for people with disabilities? No they should get real/proper tools and help/assistance. Not just a free pass to use their own smartphone. Not everyone can afford one good enough to be of much help.
Photos of the whiteboard sure but I think that falls on the teacher that they need to have that and being able to hand it out. They could of course take a picture themself and print it/photocopy.
As for laws for if they can take them that is of course needed if they are to be banned properly.
I don’t think it creates and us vs them if it’s not on the teachers to enforce it. Place the task on non-teacher staff and have reasonable punishments for trying to avoid the ban and it will work to ban them.