Diablo 2 is a game where players are largely anonymous and act as strangers to one another. This setting is more akin to the kind of low-trust situation where,

Diablo 2 is a game where players are largely anonymous and act as strangers to one another. This setting is more akin to the kind of low-trust situation where, according to Graeber (Debt: the first 5000 years), money is more likely to emerge because it doesn't require the same level of personal trust as credit systems. I've never played Diablo 2, but in other MMOs there's a concept of guilds, and people band together for specific objectives to help others get loot, level up, etc. A game akin to that would probably be a better sandbox to test assumptions around the observable circumstances in which monetary exchange could emerged from a "barter economy." In such an environment you can monitor how resources are distributed and acquired with in the guild. Do players in guilds, with in guilds, fall back on money based systems or in scenarios where one has "social credit," with in the guild to get what it is that they need?