All the points you mentioned are valid but they don't need allowing phones in schools. These students just can write down their queries and go home and study about them, if they want to learn by themselves, it's that simple.

The problem with allowing phones in school runs deeper than battling social anxiety. The problem is classism. Children from different backgrounds come to school to study, not everyone can afford an expensive smart phone and it develops not only unhealthy competitiveness among the students but also severely affects their self esteem. Classist remarks on children with poor background will especially affect their sense of self worth. Not to mention, this competition will give birth to more bullying.

I think Ms Collins is right. For emergency, you have phones at school. You don't need to bring your own.