Nevermind. I just answered my own question. It's a result of the original deck being fanned visually. So when he reshuffles the deck, the cards are still orientated in the same direction as they were in the original deck, so you get the visual side-effect of having cross-crossed cards. So you can tell approximately which side of the deck the card was from originally. And by visual estimation, a properly shuffled deck should have a combination of cards orientated in all different directions.
Which if you look at the sorting visualization links at the bottom, is actually a really effective way of showing when things are very out of order, or close to in order.
