In the dream cats and other good things to eat were even more scarce than gold. Scarcity is vital. Everyone would make themselves instant millionaires by cutting up the newspaper. Unfortunately, there would be so much of this self-made money floating around it would be worthless. Most money, however, is not paper or metal.
Most money is just numbers.
When people get paid these days, they usually receive something with numbers written on it. It may be a check that the person then gives to a bank. The bank then records the numbers from that check into the account for the person. No currency has changed hands. Increasingly today people get paid simply by receiving notice that the payor has sent the person's numbers directly to the bank.