From my non-economist understanding, the biggest difference between BTC and modern fiat currencies is that the money supply in the latter is endogenous. That is

From my non-economist understanding, the biggest difference between BTC and modern fiat currencies is that the money supply in the latter is endogenous. That is, when a bank makes a loan, the amount of money in the system actually increases. When the loan is paid back, the amount of money in the system decreases again. This means that the amount of money can fluctuate to accomodate demand at a fixed interest rate, and it does so automatically, in a decentralized way, as part of the regular operation of the system, without any government intervention. This is why it is called endogenous. Now, there are the goldbugs who think a fixed money supply is somehow morally superior. But my understanding is that experiments with controlling the money supply exogenously in the past, i.e. where the central bank set a fixed size of the money supply as target and tried to enforce that, resulted in a wildly volatile interest rate - simply because the demand for money is volatile, and by fixing the size of the money supply, something else had to budge. For businesses, a volatile interest rate is bad because it makes planning difficult. This is why central banks now target a fixed interest rate (with volatile, endogenous money supply) - it simply is better for the economy. Aside from the crazy waste of energy, this is probably the most important argument against basing the economy on Bitcoin.