Drones are mainly used by police, due to them being an effictive way to conduct survelliance, etc, than having a helicopter following. Unlike a helicopter, they use a low amount of fuel, meaning they can conduct survilliance of an area for longer, due to them using less fuel. They also got the advantage of you being able to "park" it in one specific place, and then you can kinda "forget" about since, since you can exit the terminal you need for it, and have it on your screen, just the same way as a GPS.
I've never seen any civilians using them though. From what I could imagine, it's mainly police using it.