I'll be honest, I've never heard 'unbanked' used in relation to cryptocurrency or criminals before vmception used it above.
I know my drug dealer can't pay duffle bags full of cocaine-covered $100 bills into the bank - but he can still get a personal checking account and pay in $100 a week or so. So I would not describe him as 'unbanked' in the conventional sense.
As in for example "banking the unbanked" which translates into "providing extremely expensive banking like services for criminals."