For comparison, the "fundamental" value of USD is a trust in the US Government to maintain its value. Comparing that to the fundamental value of Bitcoin would be a fun discussion to have, but the fact remains that the US has done it for 225 years and Bitcoin has done it for less than 9 years.
Actually, by that reasoning, I guess the fundamental value of Bitcoin is the distributed self-interest and capability of Bitcoin holders to maintain Bitcoin's value, which is obviously a powerful force.