Nonsense. My kid just started kindergarten this past year - I've never been required to log into ParentSquare through a GMail address and I have only ever accessed it through a browser on a laptop.

(Damn, I failed at my attempt to stop posting.)

The web is no better than phone apps when it comes to data gathering. Maybe the data is a little fuzzier, but you can be assured it's being gathered all the same as it is in phone apps.