It makes the barrier to entry that much harder. You need a driver's licence to hire a car. Sure, you can get a forgery, but it's hard to find driver's licence forgers. I wouldn't even know where to begin. So that immediately stops me from hiring a car to rob a bank or deliberately mow down pedestrians. (Not that I'm personally ordinarily tempted to, but for those who would opportunistically commit such crimes, it still applies.)
It also helps to catch the morons who still commit crimes when using their actual IDs or bank cards. It may not prevent an actual crime being committed, but it makes it easier to track down the perps. It also gives you a mechanism to withhold the ability for someone to legally obtain the car, gun, whatever if they commit a crime and their licence is withdrawn.