Crypto currencies actually make it easier to uncover dark or illegal transactions because crypto currency transactions are inherently traceable. After all, traceability is the key feature of any ledger, digital or not.
It’s precisely because paper money isn’t traceable that laws against money laundering were created in the first place.
There’s a real ethical issue with speculating in crypto currencies though: Just as with gold or fiat currencies these assets don’t create any value.
By value cash, and namely US $100 bills, are used for more crimes than anything else in the world, ever.
Don't do anything illegal with your bitcoin and you should be fine. Don't worry about what other people do, that's an endless and naive vortex of insanity. Basically mind your own business unless someone asks you a question.
If I show up to a drug transaction anywhere with a hardware wallet, I think I'd get laughed out. Yet that's not the same with USD. Or in the extreme case, If I went to Libya to purchase a slave it is safe to say they take Euros.
It's for wholesale drug operations. Usually drugs go at one time, money comes back another time. Only now instead of cash you could just use a crypto, but figuring out how to liquidate enough of it would be difficult.
Not liquidating it all would be advantageous I'd think.
OTOH the DEA would love the traceability.
So while you can buy a few grams or a slave with a briefcase of notes, it's not as easy for the dealer.
Crypto, if safe, would lower the risk by about 50%. Bitcoin is traceable but it seems that something like Monero might be better for this.
The big difference is that gold is portable and much harder to destroy.