You probably don't notice how fast you move your hands. If you lead with your body, then your lead will automatically be scaled to an acceleration and velocity at which humans can comfortably move themselves. This almost guarantees a more comfortable lead. Body leads ARE easier to follow. And in most cases less painful.
Body leads, like arm leads, can be light or strong.
The size of the backstep and the body placement determines the strength of the lead. As a matter of fact the better you get at body leads the smaller your steps become. As a dancer first learns to use his body to lead, his steps will be longer and larger. As the leader grows in skill and really learns to use his body rather then his arms, he will find that the length of his step is not as important as where his body is in relation to his foot. I believe that most people will find, when they examine how they do arm leads in a short slot, that they use a body lead to get the follower moving for the first few inches, and then they take up the rest of the slack by bending the arm more.