[imtringued]

>Money is a medium of exchange - a mechanism for judging the relative value of unlike goods. That is literally impossible if the thing used as money is non-economic, like fiat currency. The money must be itself a tradeable commodity. Commodities that are useful as money have all the traditional traits you learn in elementary school, and gold is the traditional and current best fit for those traits.

If "money" is a physical medium of exchange then advanced economies do not have or need "money".

Our modern banking system simply lets people promise each other goods and services. It's effectively a system built around relationships.