At first I thought, oh neat...but then realized, I could glue blocks of cards together to do the same thing. I am not sure the baseball analogy fits into training on the pass. Actually, not being able to practice with the actually object is what differs here - the weight, feel, texture and sound are so far off that I am unsure on how this would aid with cards, where just doing the pass with cards wouldn't?
The best tip I ever got was to use more than 52 cards, use 78 (a deck and a half) or even two decks, as when there are more cards to get around it is more effort to do the pass...also, use bigger cards, oversized, not jumbo, but ones a bit bigger than poker sized, as the same issue occurs.
When you switch back, the degrees of freedom seem far greater and allow you to switch the packets easier.
Cheers