Trying to legally define what is and is not a valid financial transaction coming in and out of Iran is a fool's errand. There's these things called commodity markets, and most everything is a commodity (more or less liquid) that can be bought and sold. Including WoW accounts, WoW gold, etc. If you wanted to launder, say, oil revenues into completely respectable US financial holdings....
And just think: due to these new restrictions, many Iranian players could get into a whole new world of encryption, non-Iranian VPNs, non-Iranian bank accounts, etc., etc. Which could have very positive political ramifications for the US down the line.
Say what you will about America or Germany or whomever in the western world, but I can still write here "Obama is an idiot" or "Merkel is a crook" or "The American Government should be destroyed, the Constitution should be abolished, and the ancient Corinthian Oligarchy should be enacted in its stead" or whatever and still sleep like a babe without any fear of repercussions.
It's far from a perfect freedom, but it's better than the alternative.