But then, how are you going to change your coin back to fiat is the other issue....
buying from a user and using will surely make some issues. To my knowledge most of the people don't try to get into such stuffs. Eventhough if something is borrowed from a stranger without proper id one can be easily tracked with these days technologies. Blankly we can't say that money laundering not possible. There might be people who has involved in it.
Politicians or business men who wants to go abroad and won't have to bring USD10K would probably be involved.
Probably expats on some 3rd world country wanted to bring their money to safety which they may have gotten it illegally. Corrupt officials are most probably into it.