Fiat should not generally be considered or seen as dirty money, even crypto can be tag dirty if channelled to the wrong cause, if crypto was all that clean why is the USA and INDIA against it?
USA is not against crypto, did you based on the statement of Trump? if that so, you don't have a real basis.
Crypto will solve a lot of problem in transaction because its decentralized, however, due to the fact that its still new, the regulation of crypto is still not that strong and people with ban intention are abusing it, if they don't like it they will just simply ban it, USA did not ban bitcoin yet.