The problem is that you cannot really control the gold&#x2F;silver supply. If your gold mines suddenly run dry (which happened to the Romans), it immediately cripples your economy (debasing the currency will create a panic, not debasing the currency leads to runoff deflation). If someone suddenly finds a massive new gold source, it will… also cripple your economy, due to runoff inflation (happened in the Spanish Price Revolution after the discovery of the New World).<p>Fiat money gives a much better control over the currency. Now we can argue what inflation&#x2F;deflation rate a currency <i>should</i> have, instead of leaving that to random chance.