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.