You say money does not have any backing, and then immediately after you say that dollars are backed with a promise from the US government. Fiat money is backed

You say money does not have any backing, and then immediately after you say that dollars are backed with a promise from the US government. Fiat money is backed by the faith in a countries economy and government. A dollar is worth something to me because I can ultimately exchange it for goods or services produced in the United States. If this were not possible, for instance if the USA completely closed their borders to all foreign trade and travel, then the dollar would be worthless to anyone outside the country. You mention that a cheque needs time for the money to be transferred. So you give me a cheque for $1, I would have to wait for the dollar to be transferred from your bank account to mine. But what if I didn't cash the cheque? What if I gave that cheque to someone else as a substitute for a dollar bill? If Alice gives a cheque to Bob, then Bob can pay Carol with that cheque if Carol trusts Alice is good for the debt. Finally, regarding the dollar being accepted for paying my government duties, that's only true for countries that have the US dollar as their official currency. If the USA disappeared tomorrow, the dollars I own would be worthless; they only have worth because they're backed by the USA, much has a cheque only has worth while a particular bank account exists and has funds.