The point that I meant to get across was that dollars have value as long as the government has power. You're right that it doesn't matter what the government says. Rather what matters is whether or not the government can back up what it says.

If you don't pay your taxes, you will be jailed. How do you pay your taxes? Well that's up the government, and they went with dollars.

I don't agree with your explanation of why dollars have value. You seem to have a bone to pick with every fiat currency, which I think is very silly.