Such use would have been developed over time with tradition being the enforcement mechanism. Any sufficiently advanced society is held together by tradition, the propagation of the dominant culture. Once again, its value is based on opinion, as opposed to the obvious value of necessary resources, animals, food and manufacturing material. Certainly its value as a currency is obvious, but beyond that it would be subject to all the forces that affect currency. Group A might have a different opinion about the worth of gold since they live in an area with far more of it than group B. The enforcement mechanism in this case is force of violence if the groups do not come to an agreement.
That is one of the fascinating things about free will trades. Neither party would engage in it if they thought they would be worse off. Hence the only logical conclusion is that both parties are better off after these exchanges. In our example war would not be a necessary outcome, since if the price was not acceptable to the one party they would simply not engage in it.
Prices are the result of perceptions and those perceptions guide people to decide what projects to tackle, what work to accept or reject and what products to buy. It indicates roughly to them what effort they are supposed to expend to get what they want. Since they can only get what they want by giving others what they want, this is how society is built economically and progresses. It is what drives innovation and is responsible for all the computer based technological advancement in the past 40 years. Speeds double every year due to profit seeking, not academic science. Engineers and scientists are hired to solve the problem of increasing computer capacities and apply their skill set to that problem. This in turn leads them to discover that which would have laid undiscovered had it not been for an economic price motivation. So both economic prosperity and science are furthered. To cut out one is to cut out both, progress will completely stop.
There are no rights. My reaction to your perceived wasteful behavior depends entirely on my previous experiences in the environment that sustained me. If I have had a limited education and lacked the skills or abilities necessary to engage you with different and possibly better ideas about resource management, then I might use force as my only option. If you lack the education or critical thinking skills to understand that my ideas are better, or have an aberrant value set that doesn't allow you to understand the consequences, and I am unwilling or unable to use force to alter your behavior, then we both suffer for your wasteful actions, assuming that they do in fact lead to negative outcomes. I know that is not a simple answer, but it is necessary to point out the inadequacy of your question.
Here is what it boils down to. If you perceive my actions as wasteful and I refuse to act differently out of my own free will, you must either suffer the collapse of your model or resort to central planning to get me to act differently. If I do not submit to the central plan, then again you must either suffer the collapse of your model (since people are acting "wastefully" and not co-operating) or you must somehow force me to do it.
Historically this is what has happened to communist countries, if the absence of free will action, and being unwilling to suffer the collapse of their model, communist governments have resorted to forcing their populous as gunpoint to execute the central plan. Once this forcing mechanism is in place things deteriorate rapidly as people are no longer able to make their own subjective decisions about what is good for them and are told to continually submit to some "authority" on the matter.