Gaggle isn't something you 'choose' for your kid; it's something your school district chooses for you. It sits in that uncomfortable middle ground between a life-saving safety net and an intrusive surveillance state.
If your kid's school uses it, the best move is to treat it as a tool for 'public' school life. Teach them that their school account is like a school hallway—don't say or write anything there that they wouldn't want a teacher or principal to see. It's a crash course in the reality that 'the cloud' is rarely private.

