Because some people like the idea of a card rising to the top of the deck(going to pocket, transforming, or whatever) without any visible handling of the deck after the card is inserted in the deck. It's just cleaner is all.I don't see why so many complex controls are made when the casual ones like this are all you need.
Well my point is that there are very simple ones that are cleaner than some of the more complex ones. Move monkeys I guess.