Dwarf Fortress used to have a currency-based economy system where the price of goods was detached from use-value and determined arbitrarily by "noble" dwarves that didn't have to do any of the work, it also included worker dwarves needing to pay rent. For obvious reasons, it made the game unplayable and was removed in a subsequent update, even though the implementation was fundamentally correct. Now the currency is just a stand-in value to facilitate bartering, as that is the only materially reasonable way to do a trade-based economy in the setting of Dwarf Fortress.