If you do it that way you are importing a good.

The end of this would not be that Steam relenting enables folks to start using foreign currency to get cheap games on a publicly traded space.

What will happen if that goes through is a swift increase in taxation of export of digital goods. You'd have countries fighting tariff wars over video games.

The idea that you can use foreign safe spots to buy and sell goods at a cheaper cost is something that only rich people get to do. As soon as it becomes broadly available to the general populace the governments crack down on it quickly.