Sumerians used silver as money to calculate debt but didn't expect to be paid in silver

It’s easy to see that “money” in this sense is in no way the product of commercial transactions. It was actually created by bureaucrats in order to keep track of resources and move things back and forth between departments.

Temple bureaucrats used the system to calculate debts (rents, fees, loans, etc.) in silver. Silver was, effectively, money. And it did indeed circulate in the form of unworked chunks, “rude bars” as Smith had put it. In this he was right. But it was almost the only part of his account that was right.

For one thing, silver did not circulate very much. Most of it just sat around in Temple and Palace treasuries, some of which remained, carefully guarded, in the same place for literally thousands of years. It would have been easy enough to standardize the ingots, stamp them, create some authoritative system to guarantee their purity. The technology existed. Yet no one saw any particular need to do so.

One reason was that while debts were calculated in silver, they did not have to be paid in silver—in fact, they could be paid in more or less anything one had around.

Peasants who owed money to the Temple or Palace, or to some Temple or Palace official, seem to have settled their debts mostly in barley, which is why fixing the ratio of silver to barley was so important. But it was perfectly acceptable to show up with goats, or furniture, or lapis lazuli.

Temples and Palaces were huge industrial operations—they could find a use for almost anything.