For nearly 3000 years coins had actual value, a system with many advantages and disadvantages. Although the Chinese invented paper money, it was the British who made worthless paper valuable by establishing a system of trust. The Industrial Revolution generated more wealth than could be paid for by exchanging valuable metal, and transporting specie around the world to pay the bills is hideously inconvenient. And lots of problems caused by the value of metal fluctuating when new sources were opened up in the 19th Century. So, gold and silver replaced first by promissory notes issued privately and by banks, which soon developed into the banknotes we know today. WW1 broke metal money because all the protagonists borrowed more money than could be backed by metal. Coins and banknotes are tokens, not valuable in themselves, that depend on trust, not metal.
The idea that money is a token has gone much further than paper. Most of the world’s wealth is numbers stored on computers, not paper, not coins, and not necessarily backed by anything physical at all. This makes us all rich.
Unfortunately, tokens are based on easily lost trust. Governments print or borrow more money than they should. Banks loan money unwisely. People gamble on stocks, shares, property, futures, insurance and other stuff they don’t understand adequately. Natural disasters, shortages, surpluses, wars, revolutions and dimwit politics rock the boat or worse. The system is vulnerable to boom and bust as the population gain or lose confidence. Value often depends on something being delivered successfully in the future. And the system is global, so risky investments made in the US sub-prime mortgage market, which crashed, end up reducing the value of the pound.
What is money? I don’t know, it’s complicated. But if coins are only tokens, sensible to make them from something cheap and hard=wearing, with no tears if they go missing, and easily replaced. No need for coins to be made of Copper, Nickel, Silver and Gold. Especially as these metals are all more useful in manufactured products than stored in a Piggy Bank!
Dave