My kids have been using these Chromebooks. I find it hard to believe that this data has any value for Google, unless they're really want to collect all the wrong answers to the math curriculum for a 6-10 year olds and the essays about favourite names for pet animals.
The location data is also useless. The kids are at school at school time.
They should just have offered laptops that don't exchange data outside the school, because it's frankly worthless to do in the first place.