A good magician conceals his tricks by revealing them. Go watch a Slydini routine (I suggest helicopter card) and really try to understand what he's saying to you. There's a message there that transcends the illusion. He shows you exactly what he's going to do, you just don't believe him because, in fact, you don't really want to know the truth.

That's why some people don't mind watching Dynamo pull some stupid shit out of a basket ball. They don't care that the only way he could have got it there is to have put it in there beforehand. The trick has one solution. What makes helicopter card so good is that it also only has one solution. The only way to do it is to drop the card back on top of the pile, hence "helicopter card". The difference between Slydini and Dynamo is that Dynamo does it off camera, Slydini does it before your eyes. Dynamo is trying to exploit the suspension of disbelief, Slydini is trying to point it out.