Banknotes and coins are fiat money. This means that citizens accept it in exchange for goods and services because we trust the issuing central bank and are certain that the money will be accepted by anyone.
If counterfeit money circulated, we would no longer trust cash as a secure means of payment. For this reason, it is essential that banknotes and coins incorporate security features that are difficult to counterfeit. Any citizen can check the authenticity of a euro banknote in a few seconds using the “feel, look, tilt” method, without using special equipment.