I thought he bought the bitcoin. He's the one who paid the commission.

See, it's all subjective characterization.

Anyone who used the site caused bitcoin to transfer from some account. It could just as well have been automatic. If the program was better designed it wouldn't have required human administration. He could have programmed a computer, gone himself to Tahiti for 5 years with no outside contact, opened a computer 5 years later and found bitcoin on account. The fact that he got some money isn't what convicted him, it's that he was THE DREAD PIRATE ROBERTS and every moron on the jury thought about a movie.