This fundamental flaw is absolutely glaring to anyone who has any understanding of economic history -- and it's amazing to me how many technologists willfully disregard several centuries of accumulated experience. Because of their built-in deflationary spiral, Bitcoins can never meaningfully be used as a medium of exchange: it will always be tempting to keep your Bitcoins in your pocket and let them appreciate instea…
Bitcoin is a commodity backed by Mathematics with the convenience of transfer of ownership through electronic rather than physical means. When the last coin is mined in 2140 the point of deflation might hold if it was a currency, but it's not. It is a faith based value store based on supply and demand, just like gold, which has next to no useful properties other than being shiny, non-tarnishing, conductive AND PEOPLE…
"Backing" is also grossly misunderstood in general.
Any "Backing" a currency has can generally be thought of as an put option on something fungible.
For example, gold will never drop below $10-$20 per Oz because of the industrial/jewelry/etc uses people find for it. However, that "backing" only makes up a small percent of the price of gold.