Safety wise, it's a central location where children can be defended while parents/guardians are working. A lot of the teachers know how to fight, and kids aren't as easy to isolate.
Academically, we already know school will be disrupted by the cruise to some extent. So people who want to learn in the classroom environment probably don't want to lose more time than they have to. Plus, if they feel safe it's easier to learn when you aren't looking over your shoulder every ten seconds.
I'd say learning is important. Whether or not that's in school depends on circumstance.