Let's consider this scenario. What if iron - an absolutely seminal resource for industry, commerce, and human life in general, let alone modern or contemporary living standards - was in scarce supply as gold, and governments around the world would operate under an iron standard? Governments would allow their IOUs recorded in paper or electronic entries to be converted into iron on demand. What would happen?
1- I doubt we'd have modern electronic banking in this world/history scenario to begin with.
2- It would be expensive as HELL to use iron in industry, because everyone is using it as medium for debt or money (money & debt are the same thing). Because people are using this seminal & scarce (commodity) iron to pay taxes, to transact, and to save.