It is easier to write anti-fraud algorithms for other goods: If you want to buy stuff and ship to Romania with a US credit card, that will raise a lot of read flags I'd imagine.
You also have to resell the goods which is probably quite a hassle. There are of course a things that are almost as good as money, like gold and stuff, but the sellers of that probably have their algos set for very few false positives.
Google anti fraud api, it is quite interesting.