Around 10 years ago before the rise of bitcoin, WoW gold was the de facto illicit currency of the internet, since there was a reasonably robust market for it. Things like batches of stolen credit cards would routinely be bought and sold in prices delineated in WoW gold.

According to a Blizzard employee one of my coworkers talked to, their chargeback rates were significantly higher than even porn sites (15+%, IIRC), to the point that it was somewhat surprising that their payment processor was still doing business with them. It's unclear to me if those accounts were primarily used to generate mules to facilitate these transactions, gold farming, or something else.