My personal opinion is that crypto-currencies have an inherent value of zero. That said, the federal reserve note is worse than that, as it's a note that is due back to the federal reserve with interest. Because the crypto-currencies are supposedly decentralized, my opinion is they are better than the dollar but not as good by any means as something like gold or silver or some other tangible hard asset. The utility of cryptos, however, make transactions much easier than using hard assets for that.

These are good questions and we certainly live in interesting times.