I thought that way at first as well, as we were doing a more baseball-type, striding swing which finished with the rotating hip pulling back foot forward, toe-down and dragging, however many aspects of this current method were encouraged by another highly-regarded scholarship swing-builder from the Chicago area (not the Epstein Guy - I don't want to throw anyone's name out there without their permission, though).
I believe the premise of the back-foot mechanism I mentioned is that we have a more massive ball, and the back foot coming off the ground, or up on toe, does not carry mass forward as well - or probably not until you are old enough to swing a heavier bat. If you watch a lot of college girls swing, you see that back foot even sit back onto the ball again at the end of the swing in an effort to power that barrel through that massive ball.
A baseball, however, has a superball in the core (whereas a fastpitch ball is just solid cork), so its elasticity quotient is much higher - you can pivot on front foot on heel and drag up and forward on the tip of that back toe a lot more confidently when the ball springs off the bat like that.
I don't know enough to take sides her, but my experience has been that those who ''finished with the rotating hip pulling back foot forward, toe-down and dragging'' might actually get more power, but at the risk of some accuracy.