Changpeng Zhao, the billionaire founder of the Binance cryptocurrency exchange, arrived at the Coca-Cola Arena in Dubai to rapturous applause and a long line of fans eager for a selfie with him. Deep in the pulsating crowd, a man yelled “he is a martyr” while in another part of the room a promoter of a startup boldly declared: “the king is back!”Back, that is, from a US prison halfway around the world. Yet the crypto billionaire known as CZ isn’t back at the helm of the largest crypto exchange, ...