So what? Say you have an account X which holds funds from criminal operations (e.g. ransomware payments). If you cash it out directly there's no doubt you're a criminal. But if you use that money to pay yourself for an NFT, now you can possibly deny that you have any knowledge about source of X income.
Better yet send money from X through a bunch of privacy oriented tokens like monero, tumblers and mixing services, losing 20-50% in the process and consolidating the rest in account Y. Now you have plausibly clean money but you can't pay taxes yet as there's no paper trail for this income. Solution is easy, buy an NFT from yourself, declare it, pay taxes and buy a new yacht.