It's difficult to feel a sense of belonging if all your peers have access to something you don't, even worse if that something is your social space itself.

(Full disclosure: I am rampantly anti smartphone. But I understand kids' need to have it.)

* Use an LMS called Infinite Canvas. Among other things, the kids have to submit homework online -- which can be done on the web app -- which often requires them to take a photo of handwritten work to upload. Have you ever tried taking a photo of a piece of paper using a $200 Chromebook?

* Use Teamsnap for sports team management: scheduling, roster management, messaging, etc.

* Use Instagram for school-official communications, including things like social events, counseling services, college visits, and sports team news.

... There are more, but the point is that phone apps make certain things easy and schools are taking advantage of that fact, even if they're simultaneously banning them during school hours.