It had a brief appearance shortly after the .40d era.
It was VERY buggy. Every noble in the fortress was in a constant pissing match of who set what prices on what items, which *ALWAYS* boiled down to selfish "I really like [Green glass gems]! PRICE IS NOW 500% higher!" insanity.
Additionally, all rooms suddenly had rent that was due-- causing many dwarves to be unable to afford to be alive (food cost currency units, drinks cost currency units, sleeping in a room cost currency units... etc.... And the amount paid for normal "these jobs are not glamorous, but are essential to running a fortress" like item hauling, paid so little that it was just sad to watch), making fortresses that WERE thriving and very healthy suddenly go into full on tantrum spiral in minutes as soon as the baron showed up. In addition to that, if you were stupid enough to actually mint coins, dwarves would spend all their time pushing stacks of them around instead of doing jobs that actually paid them something, and so the problem was greatly magnified. (most people eschewed the minting of coins for this reason.)
It was subsequently disabled (though I understand the code is still present and can be turned on with dfhack) in later versions, and the players rejoiced.