Valve already sent out C&D letters to the enabler sites under the pretense that what they were doing was a violation of the EULA. Of course it's to late to starve off the lawsuit, just like their refund policy was a reaction to those lawsuits.
These types of microtransactions aren't new. It being such a blatant gamble is why you can't buy individual items directly. With Steam you have to use your steam wallet, with Pokemon you have to first buy their coins. That way when the game of chance doesn't go your way you can't do a charge back or file complaints. You were given what you paid for, whatever you gambled that on is your own decision.