The fiat offers, at minimum, a requirement to do transactions in that currency to some minimal degree, as you are required by law to pay taxes (notice that taxe

The fiat offers, at minimum, a requirement to do transactions in that currency to some minimal degree, as you are required by law to pay taxes (notice that taxes are applied to all exchanges, in theory at least, not just those conducted in the fiat currency) in that currency or go to jail. That is the minimum it offers. It also offers the ability to transact with the government, who is the largest sole consumer in our economy, and a whole host of other things.