Known as https://en.wikipedia.org/wiki/Chartalism, by the way. :)

While these risks clearly _do_ apply to traditional currencies, I do think, as an investor, it's worth considering market cap (as a proxy for "social belief in") and history of stability.

Bitcoin's market cap is probably (factoring in permanently lost coins) something like $750B, which makes it a bit smaller than, say, the Swiss franc, and its history of stability is much, much shorter.