I think it goes a bit further than that. Bitcoin has enabled some crimes that just were not possible beforehand. I'm thinking of large scale desktop/laptop ransomware in particular. We've seen this kind of malware now routinely asks endusers for bitcoin to unlock their desktop once they've been caught by it. Police forces are unable to follow the money, a key route to catching malware authors up until now.
Yes but the point was made that bitcoin isnt being used to buy stuff, so what use is it?
If I received 1,000 BTC through a malware scam, happy that the cops cant trace me, what good is a 1,000 BTC (€14m) if I cant spend it?
Typically, I would imagine, I would sell all or part of it, putting downward pressure on price of BTC.