The point of ABS is to prevent your wheels from just locking up completely which allows you to still be able to steer to some extent. If you just lock up your brakes, all you can do is hang on for the ride, but with ABS, you may be able to steer yourself out of a situation.

ABS can actually cause your braking distance to increase slightly on some surfaces like gravel, etc. it doesnt necessarily stop you shorter all the time, its mainly a system that allows you to maintain some control of the car.