Instruction I had when this Law was amended was that it was done because it had happened on a number of occasions where the ball had been dropped in a non-contested DB and the player kicked it toward the other goalkeeper, but... it went straight into the goal instead. The reasoning behind it was to force the player to take at least two touches on the ball. So a player can get the drop ball, dribble once or twice then kick it into the goal and that's fine. That's a goal. Otherwise, it's a goal kick or corner kick (depending on which goal the ball was kicked into) if it's kicked in the goal with the first touch.