Money is defined as a commonly accepted medium of exchange. Yes, anyone can create IOUs which satisfy the abstract idealization of money as a "numeraire", but i

Money is defined as a commonly accepted medium of exchange. Yes, anyone can create IOUs which satisfy the abstract idealization of money as a "numeraire", but if these IOUs are not commonly accepted for commercial transactions then they aren't money. This is an empirical definition, which is perhaps less useful for theoretical arguments. Banks which participate in a central banking scheme (such as the Federal Reserve System) have a license to create IOUs which are authenticated by the government which sponsors that central bank. In other words, such banks can create IOUs that are backed by the full trust and credit of the government, not merely their own trust and credit as a business enterprise. I'm not sure I would characterize this as "impressive", but it is most certainly a privileged and unique position over the rest of us.