Prices, from anonymous
One of the greatest features of any market is they enable price discovery. The words are almost interchangeable. Markets equals prices. Once a price is established from hundreds, thousands or millions of transactions, then the laws of supply and demand, scarcity, comparative advantage, can kick in to allocate resource to create the greatest aggregate wealth. Also things can be measured when there are accurate prices to study baselines, make comparisons, and determine trends. The opposite would be true for industries where there is no price discovery. I can think of one big industry prices where discovery is notably absent and there is much waste as a result.