This kind of thinking is very warm and fuzzy with one or two pigs, and much less so when it's on the scale of billions.

I don't agree. Instead of being between two people, think of the transaction as being between a person and society. Since society offers a lot of different things, you can sell your pigs to society for a token which you can later use to redeem goods and services later. In this sense money is a debt - or an IOU - from society to the holder.

People create money substitutes at will when their central government isn't providing them with a suitable money system. That should give you an intuitive sense that money is always a social relationship.

A bank acts like an internet router but one that transforms the risk relationship. It is not an intermediary that accepts deposits and lends them on. It is an intermediary that acts as a third party to a double sided debt contract where one side owes products and services to the creditor and another side owes money to the debtor.

well, there's like 800 million pigs in the world today as-is, so...