Why were coins a better form of money than flat money?

Coins were a better form of money than flat money because they provided a standardized, durable, and portable medium of exchange. Unlike flat money, which can be easily damaged or counterfeited, coins are typically made from metals that hold intrinsic value and are harder to replicate. Additionally, coins can be used in a variety of transactions without the need for additional verification, making them more efficient in trade. Their tangible nature also instills greater trust among users compared to paper currency.