...are really useful things. They can hover for extended periods, they can land on small areas.
However, they do need reasonably flat surfaces to land on - which is why many helicopter rescues involve a winch. Winching up an injured person is risky.
DARPA has a solution - telescopic landing gear equipped with sensors that allow each leg to adjust to the terrain underneath. And they've demonstrated that it works - on an otherwise completely unmodified helicopter. It also makes it easier to land a helicopter on a ship.
The new landing gear (which also should reduce damage to the vehicle from tricky landings) isn't exactly available commercially yet, but once it is, it will make helicopters even more useful than they are already.
(Now to come up with a way to sneak this into a story).