speculation

You have probably heard it before: „Dishonest speculators are manipulating asset prices extensively. They make unjust and therefore undeserved profits. These vicious individuals only enrich themselves immorally at the expense of society as a whole, whose members, unlike them, depend on honest work to obtain scarce resources.

To understand utility of an intermediary we need to understand subjective price theory. A can of cheese does not have a universal value given from the “universe”, but rather N subjective values which vary in time and space. A task of the intermediary is to exchange what we need less for what we need more.