[Yoda]

Why is that?

Is it so that the Pivot can get out of the way for the hands to take a straight line path down to the ball?

Is it also because of Pivot Lag? Do Hitters even have Pivot Lag?

The short Pitch Shot requires only an Acquired Motion Backstroke (Right Forearm parallel to the ground) or even less. This is near the bottom of any Full Stroke Sraight Line Delivery Path, and there is little, if any, Straight Line Path remaining for the Hands to take. So, we're basically talking Circle Path Delivery, even though the Thrust will be Straight Line (toward the Ball).

Except for truly incidental Body Motion, the Pivot should work from the Feet up -- Pivot Lag -- and lead the Hands through Impact. This is true for both Hitters and Swingers.