The whole point of preventing the brakes from locking up is so that you can steer the car under heavy braking. Without ABS, if you were stomp on the brake pedal and lock up the tires, the car would just continue forward, maybe swerving a bit to one side without you being able to control it. With ABS, if you stomp on the brakes, they will not lock up and you can still steer the car away from whatever you are trying to brake for.