[mulberry_seas]

Isn't it coercive in the sense of the monetary "rules" being hard-coded? Lawrence Lessig says this is "East Coast Code" as opposed to West Coast Code in his book "Code 2.0".

Anyways, even if it is non-coercive in the sense of having no West Coast Code or legislative coercive forces at play, you can still learn a lot about monetary economics in such environments. This author is interested in the emergence of monetary exchange, and that's a pretty big literature for instance, going back to Menger's "On the Origin of Money" (though Menger does note the later imposition of standardization from political authorities, etc.) and more analytical work such as Duffy & Ochs (1999).

This literature on the emergence of currency/monetary exchange from barter exchange typically understands such emergence to occur independent of any such force - all you need is the existence of the problem of double coincidence of wants. What I have in my inventory may not match what you want to trade for in your inventory, so some object that is marginally more "saleable" in the sense of being more widely desired, easier to carry, etc., will emerge as a currency standard. Also see Radford (1945)'s study "Economic Organization of a POW Camp" where cigarettes emerged as a common currency.

[pasabagi]

I was thinking of coercion in the sense of, normally market actors are also vulnerable humans, who need various things from their communities to survive, and if you don't behave in certain ways (selling your labour, etc) you cease to get those things.

In Diablo, you can be a pretty rational economic actor, because there isn't this impinging plane of crushing material need distorting all your decisions. As such, it's not necessarily a good model for understanding real world economic behaviour.