Since a commodity money supply cannot arbitrarily be expanded, interest rates would increase if government increased borrowing. Manufacturers and others would then object to higher interest rates, causing government to reduce spending, and thereby causing deficits to decrease. Eventually, the debts are defaulted. Commodity money tends to facilitate lower tax rates and less taxation, since citizens see how much is being extracted from them. As fiat money is created out of nothing, there tends to be inflation and ordinary working people are pushed into higher tax brackets.
People pay a larger percentage of their income to taxes.
With commodity money, real wages tend to increase, as does the standard of living. With fiat money, real wages tend either to stagnate or decrease, as does the standard of living. There is good data from Great Britain going back almost 200 years attesting to this. Interest rates are much higher than with commodity money. Commodity money facilitates real growth by investing savings, thereby causing increases in physical and intellectual capital.