Obviously that's not the only use for the helicopters. Just a very small fragment of its use (despite so many people in this sub going straight to that as the reason for it being wasteful spending). As OP pointed out in another comment, they're at least used to follow stolen vehicles which are often the result a car jacking.

Also, 5 lifeguards wouldn't work. We would need 24/7 lifeguards because children trespass at all hours.