That’s the policy at most schools. Actually enforcing that in the face of a classroom of kids who don’t respect the rule? That’s a much bigger problem. They’re a lot more clever at sneaking them out than you would think. Moreover, if the phones are just feet from them, their presence is never out of mind. They’re a constant distraction even in a bag. Phone apps are literally designed to be addictive. Imagine if we had a rule that said “crack pipes are fine in your bag. As long as you don’t take them out and smoke in class, you’re fine.” Even if we lived in a world where crack somehow was legal for minors to have, how effective to you think that rule could be enforced?
This is true. Long range missiles like this are only practical with either nuclear warheads or modern precision guidance. If you can land them right on top of a tiny target, they’re useful. If your target is an area miles in diameter, they’re also useful. But back in WW2 they were just vanity projects.