Its obvious that fiat has been used for alot of criminal activities
, because 95% of the total world population uses it, unlike crypto which is being used by a few fraction people, fiat has been used in distant time to commit all sort of crimes while crypto has being around for about a decade now, but I think using crypto for money Laundering is alot more easier, less risky and more safer than fiat, because it helps to hide your true identity.
well, I totally agree with what you say, but you also need to know that digital currency cryptocurrency is also often used for crime and even money laundering that can be done by anyone who is familiar with cryptocurrency.