then he's referring to banknotes as well. creating money out of a blank sheet.

banknotes are just printed on paper and is backed by the word of the government. the government says that banknotes/fiat are valuable and the people believe it. when the government devalues money, or declares that a certain banknote series will no longer be accepted as payment, people will believe it. if you keep a large amount of that banknote series that was devalued by the government, that would mean you're instantly broke!