Thanks, a good explanation. And I don't think money has an inherent need to be government controlled in order to be stable either. (Though I do see some benefits)

But I think it's relevant to split hairs a bit and say that "sound" often has the sense of "firm" or "solid/reliable", but that is not an inherent property of non-governmental currencies that can be controlled by groups that are no more beholden to users of the currency than governments. (Consider Facebook's attempt at creating a currency as an example)