I have to sympathize with Penn & Teller here. A lot of magic is in misdirection. You know what your hands do. You see the magician’s hands, and you assume they are doing the same. Add a fake finger so you can hold something in an open hand. This guy - you are looking at his not-hands, then you are looking at his face because staring at them isn’t nice, then you are staring at his not-hands again. I feel this cannot be predictable enough to work a misdirection; and anyhow it is focusing attention on where the trick seems to be happening…
I’d argue that still calling it “sleight of hand” card magic only adds to how awesome this guy is. To do sleight of hand without hands makes it that much more impressive.
“you guys actually have to use your hands to do “sleight of hand”? psssh!”…
He didn’t win (unless he won later or something). They have an IAMA video in which they insist they never “cheated” one way or the other and mentioned Piff as somebody they actually hoped would fool them, but didn’t.
Worth pointing out that the real purpose of the show is to showcase great magicians in ideal circumstances. Fooling P&T is a bonus but getting exposure, and thus more work, is the real goal. By that token, Piff the Magic Dragon, who didn’t fool them, is a big winner.
Mahdi is such a unique and inspiring individual that he is sure to explode after this. Fooling P&T was just icing on the cake, and I think it happened because they made the deadly and probably common mistake of underestimating him.