There is little purpose nor function for having internal commerce and every function that supposadly requires it, the commerce side of things turns out to be a redundant irritant. Largely what we want is dwarf behaviors and hardly any of them require that money be involved at all.
I respect your opinion. However, I am curious as to what game you have played that involves internal commerce. On what do you base your opinion? And of course none of the behaviors of dwarves, regardless of what we want, require money be involved at all. Keep in mind that nothing I have suggested requires money even exist. And value and price doesn't have to have anything to do with money.
Also, no dwarf behaviors, planned or existing, require money. But a lot, if not all, require some method of ascribing value to things in order to make believable, non-arbitrary judgements that have some degree of predictability and (more importantly) use. And right now, commodity value is not handled well at all. And hopefully by the end of this post I will make it somewhat clear as to why this will need to be addressed and why internal commerce (as opposed to just taking things as needed from communal stockpiles) is something that is often needed for effective resource management that maximizes happiness, productivity, etc. (in other words, avoids tantrum-spiral death).
The person you link too just looks like the usual economist snake-oil salesman insisting that if only his own pet real-life economic ideas were implemented in the game then everything would work smoothly.
What a sad and ignorant thing to say, especially without any meaningful evidence presented.
Being dismissive of ideas without critical thinking helps nothing.
What we fundamentally need is for individual dwarves to demand specific items from the player, which are then collected. Dwarves that estimate their value higher make more extravagant demands of the player. If we want to keep a specific dwarf happy then we could even fine-tune things ourselves by having his personal demands highlighted say a particular colour or highlighting those demands that specifically pertain to dwarves that meet the criteria.
First off, for the following, I am only talking about stuff going on in the fort, and am not talking about anything relating to the outside of the fort, including visiting merchants, etc.
Indeed we do need a way for individual dwarves to make demands. And, guess what?
We DO! Just take a look at the nobility in the game. However, these demands are really really basic, and the way these demands are communicated to the player leave something to be desired. As things are right now, other than subsistence demands universal to all dwarves and entities, the demands of the nobility are quite arbitrary. And the demands of all entities in so far as basic survival needs are not directly communicated to the player, though one could determine the consumption of this or that commodity by dwarves in a fort sort of easily (though it would could be time consuming) by looking at stockpiles and doing simple math. From there you can determine how much of this or that you need to make (well... have your dwarves make) for a given population and scale up as more people come to avoid tantrum spirals. Fine. This is pretty much how gameplay is right now (though we often do nicely without the math). From the demand you observe, you determine value (in a manner of speaking) and affect supply of whatever it is that is demanded.
So, from what I understand, all that you are suggesting is a way to make exactly what I just mention not an aspect of gameplay the player really needs to actively participate in. That is fine. And it would be fairly straightforward to have the computer do this to an extent (provided enough workshops and infrastructure and resources are available to assign appropriate jobs). And this works just dandy with dwarves and entities in the game as they currently are (other than nobles), since they have little to no personal goals, and little if any way to make value-based judgements on their own about what they are willing to give for something else to satisfy their goals (with the exception of pathing). They will pretty much work and do whatever you tell them to (with few exceptions) so long as they are not in a tantrum.
However, this system might not be robust if behavior of dwarves ever become more complex and realistic, particularly if they ever come to have any sort of personal goals. And, actually, in a way, the kind of stuff I mean is already really loosely present in nobles... Anyway, if all dwarves (and entities in general) become able to exercise a bit more autonomy, come to have a way of ascribing value to things (as in... I am willing to give this much of my time towards carpentry to receive X plump helmets) and have individual goals in mind (as in... I want to have a big domicile in a reputable fortress in which to raise my family), then I wonder what will happen... As things are now, if a (non-noble) dwarf meets all their hard-coded needs, they just sit around doing nothing. Otherwise, they either die or throw a tantrum. Now, don't get me wrong, DF does a pretty damned good simulation of individual behaviors, definitely qualitatively MUCH better than a vast majority of games and simulations out there. BUT you do not have you average dwarves acting as anything except mindless ants (that could blow up at any moment).
Nobles are another matter. They make demands that, if not met, lead them to become unhappy. This in principle is pretty realistic of not just nobles IRL. If I don't get to do or fail at what I want to do in life, I get depressed and/or angry. I'm sure the same goes for all of us forum-goers and any human being ever. Anyway, though the demands and mandates of nobles are arbitrary, even if they weren't... How many times would it take for you to wish that damned noble could just go do things by them self instead of you having to make it work (and ultimately interrupting your own goals for your awesome fort)? Now imagine if every dwarf in the fortress, as they would in real life, also had their own demands beyond immediate survival? This would be a rather tricky thing to manage centrally (possible, but tricky... just look at any centralized economy). If this happened right now, then individuals in your fort would have no way to meet their needs/wants other than waiting on you, the player, to micromanage their asses even more than now to make it all work (which, admittedly, might be a fun game for some in its own right).
THIS IS EXACTLY WHERE INTERNAL COMMERCE WOULD BE A GOOD (not to mention, realistic) THING. It would give the tools for dwarves (and any entity in the game) to exercise their autonomy towards meeting their individual wants and needs instead of exclusively relying on a hive-mind or greater power (you) to do so and/or just taking things from communal stockpiles willy-nilly. How free this commerce is (or whether or not it exists legally in the first place) would be completely up to the player (so, you could easily do things the GoblinCookie way if you wanted to, and it would work beautifully in some circumstances!). And the role of the player in ensuring the success of whatever system of economy will lie not necessarily within micromanagement of individuals, but in management of the fortress as a whole, including infrastructure, economic policies, etc.
It sure as hell isn't an issue now, but look at the development pages with regard to the behaviors of individuals and groups in fortress mode.
I hope I am making sense... I will revisit this later.