I think many bad people or criminals use fiat and the other currencies often to make the illegal activities before the Bitcoin's create. So we can't accuse the bitcoin's currency to being used by some people for this illegal purposes
Even now, 6 years after the creation of bitcoin, US dollar is still the favourite of the criminals.
Well sure, that's like saying mansions, hookers & blow are still favorite with criminals. Criminals simply use Bitcoin to get at USD, just like they use USD to get at hookers & blow.
Caveat: Everyone uses real money, mostly criminals use BTC
