What you want to ask is the reason why banks don't exchange expired dollars? Because it doesn't circulate.

At present, the country will only keep the foreign currency in circulation. The old version has been withdrawn from circulation and domestic banks will not exchange it.

The competent department for issuing US dollars is Congress, and the Federal Reserve Bank is responsible for the specific issuance business. After World War II, continental European countries reached an agreement with the United States to use US dollars for international payments. Since then, the dollar has been widely used as a reserve currency in countries outside the United States, and eventually became an international currency.