With privacy coins and decentralized exchanges, KYC no longer becomes an issue. Criminals can remain out of the radar if they make use of decentralized and anonymous alternatives. The reason why most of them are using Fiat on top of crypto is because Fiat is stable. Not to mention, most merchants and businesses accept Fiat as payment method. Crypto's wild fluctuations in price tells us that it's more suitable as a speculative instrument than a real currency for day-to-day payments. I'd prefer criminals to stay away from crypto as much as possible so governments can give the "green light" for the industry's growth. The more legitimate uses crypto has, the better it'll be for its mainstream adoption. Just my thoughts