The world has changed a lot since the 727 was designed. So did the brakes of almost every aircraft type.
Modern carbon brakes are completely different than old metal brakes. Carbon brakes wear down with times of application, not with "braking power". As the auto brake is perfectly in applying brake pressure only one time it is to be preferred over manual braking.
Nevertheless a little bit of thinking should not be forbidden: If I want to leave the 4000m RWY at the End with an A320 the only reasonable choice will be Autobrake OFF.
