The value is providing the ownership of a digital scarce fixed-supply item that can be transferred and traded.
That's the product. And the market gives it a price.
Also, it has everything to do with monetary policy.
There are 8000+ cryptocurrencies, some (or a lot?) of them are bitcoin clones. Most of them issue millions and billions of those digital items. It's not scarce at all.
There is a difference between short term utilitarian value and long term utilitarian value.
BTC might have no short term utilitarian value, but in the long term the utilitarian value is to create a globalized monetary policy.
1. BTC is speculative because it may not actually achieve the goal of a single globalized monetary policy. Some other crypto might become the defacto denationalized currency instead, or maybe nothing changes.
2. A single globalized monetary policy may not be useful. However, no one really knows. People investing in any crypto seem to believe that a denationalized monetary policy will be better functioning.
Speculation alone doesn't imply no long-term utilitarian value exists.
Great question, but I'll answer a slightly different question.
> If and when we have a globalized monetary policy, how do we run it without burning more energy than entire countries?
1. You could get all entities governing the market / governing the globalized monetary policy to perfectly trust each other. Seems impossible given the Prisoner's Dilemma is exponentially more difficult to solve as the number of actors grows.
2. It is outside my domain of expertise to know how we can make a trust-less ledger efficient to run. The engineers behind ETH and Nano seem to believe it is possible.
However, given 1. is an impossible problem, and every unique entity that governs the globalized monetary policy will be competing with each other for control. They will all compete in an arms race to control as many crypto nodes as possible (i.e. a war of energy production).
It seems like the amount of energy needed will always be larger than most countries use because otherwise any one country can spin up a 51% attack very easily.
This doesn't mean crypto energy consumption will spiral to infinite as the world's super powers compete. Because, the world's super powers already have to worry about "mutually assured destruction" and as such can "trust" each other not to trigger a 51% attack because that would be treated as a global signal to launch nukes[0].
And like nuclear de-armament, there will likely be a push for the super powers to consume less energy while protecting against a 51% attack. There will be some interesting equilibrium. My guess is the equilibrium will probably be around the energy consumption of the p99 country sorted by energy consumption.
[0] I've never thought about this before, but a 51% attack could be an automated signal to launch nukes. I hope no country removes the humans from the launch process.
> Could we do this without burning more energy than entire countries?
Based on my (arguably poor) ability to predict the future the answer seems to be a "No, crypto energy consumption will always be more than most countries".
Other people like the ETH and Nano developers seem to believe the answer is "Yes it is possible to be more efficient with crypto mining". However, I don't know their stance on "Will the energy consumption still be more than most countries?"
Nobody accepts it as payment, because its value is too volatile, speculation-driven, and nobody wants to spend it, because it is deflationary.
And that's not even considering the fact that it can only be transferred at around 6 transactions per second, less than 1/10,000th of the transaction volume of Visa.