I'm all in to get programming classes where children learn to code on PCs. That's a high pass for me. But AFAIK children aren't doing programming on their phones.

In general i doubt using a phone at school is going to help them program or teach them about technology. They have plenty of time to explore phones on their own when they get home, especially now that kids don't go much outside anymore. It's not like a school ban would be cutting that away from them.