Guild Wars 2, so no way to actually turn it into real currency that I'm aware of (unless you sell your account or something); I mean, you can convert "gold" (game currency) to "gems" (game store currency) but gems can't purchase anything other than GW2 items, which are all virtual and contained within the game and your account.

But that is an interesting thought. I'd be curious to read such an analysis.

Also, it occurs to me, one area of potential interest about GW2 in terms of economic analysis is the internal design of the economy. Though I'm not real familiar with the specifics, there are players in the game who play the trading post like a game of its own, amassing in-game wealth with things like flipping, or (anecdotally I've heard) with organized attempts to control the market for specific items in order to make more off of them. Ultimately, GW2 devs can step in and wreck this pretty easy by adjusting how easy it is to obtain items, but a particular one I recall this happening with is the "black lion weapons", which are uncommon or rare drops from GW2's lootboxes. GW2 devs solution to this (as I understand it) was to have these items come back every so often on a rotation, so that supply would not become too rare. But nevertheless, you can see how certain items like this end up with fairly consistent, high cost to buy from other players on the trading post, suggesting people are actively manipulating it. As opposed to more random range of listings and availability if they weren't.

One player on reddit even actively admitted to doing market manipulation with the essence that drops from this item: https://wiki.guildwars2.com/wiki/Mystic_Chest though I don't know if they are still playing now

And there is potential analysis to be done in how people like this are probably being allowed to exist in a game economy because, in some cases, they actually make it more stable, even though their greed is not good for players; the company itself can benefit from it if it becomes harder to get certain rare items as a result while having consistent supply listed, such that players will be tempted to spend real money on gems, convert it to gold, and then buy the item off the trading post.