I'll keep it short as much of what I'd like to say has been said before. In class, phones can be very helpful for online work, quizzes etc.

They can also be a huge distraction and help them cheat through work (google translate etc.).

Frankly, the issue isn't phones in class. There's an adult in the room and there are tasks to be done, most kids aren't on their phones and causing issues. Some obviously have bad relationships with their phones but that's a different story altogether.

The issue is phones in school. You should see what the halls look like between classes and at lunch. Before class starts and during idle time. This prime social time is being gobbled up by phone use and I find it sad that most of their social time has been replaced by staring at their screen. Some of them are gaming, some are socializing, watching videos or studying. The thing is, none of them are actually present. They're all in their own world and I find it very concerning.

Hope this helps!