That's the thing here. We're so used at the concept of money that you described that it's very hard to reconcile with what money really is.
You can take any introductory banking system course and it will tell the same story. (I recommend Economics of Money and Banking by Perry G Mehrling)
It's not really a finished exchange.
Money represent a debt.
It's a one sided exchange against the promise of the completion of the other side of the exchange in the future (by someone else in this case).
It's like the amount in your bank account is not really money. It's a debt from the bank: the promise that it will deliver this amount as cash if you ask. (M1)
And money is so liquid that we never think about it that way. Except during hyperinflation periods. And bank account are so solid that we think about them as cash. Except during bank runs.
As a side note, the theory that barter really meaningfully took place is being challenged as there is no real evidence of this.
Looking at the fine print of bank accounts, I would assume they completely absolve themselves of responsibility after a catastrophic event (call it C-Day). Or maybe they defer to FDIC insurance which guarantees I will have at least $250,000 after C-Day.
That said, as a consumer, I have no comprehension of how that would actually work. Do I get my guaranteed money 7 days after C-Day or 6 months after C-Day?
If an EMP blitzes my bank's electronic hard-drive records, is it my responsibility to prove I had X dollars in the account? If so, how? I can easily print a statement, but a statement clearly easily be forged. If it's the bank's responsibility, is there any guarantee they maintain physical and up-to-date records? Is there any regulation mandating they keep such records?
What happens if hyperinflation occurs and the 250,000 guaranteed by the FDIC is enough to buy a week's worth of groceries?
There's a lot of unknown variables and potential fragility in the system.
In other complex realms like software engineering, we get evidence that those complex systems really only have the budget to build the "happy path" and lawyers fight the cases when customers get damaged by the "unhappy paths."
It seems like our monetary system is on the happy path and very few times have the unhappy paths been tested.
You can take any introductory banking system course and it will tell the same story. (I recommend Economics of Money and Banking by Perry G Mehrling)
It's not really a finished exchange.
Money represent a debt.
It's a one sided exchange against the promise of the completion of the other side of the exchange in the future (by someone else in this case).
It's like the amount in your bank account is not really money. It's a debt from the bank: the promise that it will deliver this amount as cash if you ask. (M1)
And money is so liquid that we never think about it that way. Except during hyperinflation periods. And bank account are so solid that we think about them as cash. Except during bank runs.
As a side note, the theory that barter really meaningfully took place is being challenged as there is no real evidence of this.