The gain of seigniorage from paper money is greater and is just as easily secured as that from coinage of metals.
Governmental paper money is called "political money," in contrast with commodity money.

However, all coins that contain an element of seigniorage, or monopoly value, are to that degree "political money." The typical paper money is irredeemable; that is, it cannot be turned into bullion money on demand.

It is simply put into circulation, usually with the "legal-tender" quality.

Money has the _legal-tender_ quality (as the term is used in the United States) when, according to law, it must be accepted by citizens as a legal discharge for debts due them, unless otherwise provided in the contract.

The prime purpose of making money legal tender is to reduce the danger of dispute as to payments; but another purpose often has been to force people to use a depreciated money whether they would or not.