Nope, I'm suggesting that we should be able to choose which currency to use. But now we can't.

If we could, we'd choose a sound currency, and then our purchasing power would keep increasing steadily (because of productivity improvements and wealth accumulating over time).

We can't? I mean, I have to obtain USD to pay my taxes, but otherwise I can use currencies at will. I have a hard time finding anyone local who will accept or pay me in anything besides USD, but that's their own choice to do so.