I don’t think it is down to the pupils. I think that depends on their teachers & schools. If it is part of learning in school they will use it for that. And for staff who are not confident with digital it give at least some assurances & help.
Glow services goes through rigorous data protection. There are plenty of digital enthusiasts who could can find and incorporate “better” tools or ones that meet the needs of their particular classrooms. That might lack a little on the safety front and many be difficult to sustain. Having a national solution avoids some of those problems.