Most children know how to use a cellphone even if they don't have one. A lot depends on the circumstances, if the child gets the bus to and from school, a phone would be useful if the bus was late, or to tell the parents they missed the bus. For children that have different people picking them up it's important too, so they can relay that information to the child. I know when I have been to pick up my cousin's son, she has to inform them who will pick him up. A phone doesn't need to have any gadgets on it, so the more basic the better, which is why they should still make basic models which I know many companies shy away from these days.