Because it works... The level of counterfeit currency is readily measurable. Currency can be withdrawn and replaced. Individual stolen notes can be tracked. Counterfeiting of the dollar and the euro today is a relatively minor problem

https://www.ecb.europa.eu/press/pr/date/2025/html/ecb.pr2502... https://www.bankofengland.co.uk/statistics/banknote https://www.cranecurrency.com/news-insights/85-decline-in-us...