Of course something only goes up in value if someone is willing to pay more for it, that's true of art, cars, houses, or whatever. You could argue that a house has more utilitarian value, as you could always live there, but that completely ignores the other persons goals. A house isn't going to be much value if jobs are scarce in that area, but bitcoin would still have value in that scenario.
All that energy is going to make sure you can send a large amount of value between two parties from almost anywhere in the globe with a minimum of transaction costs and a decent amount of anonymity.
This also ignores the fact of risk pricing. I live in Backwatermenistan and the political stability and the currency is looking unstable. I could buy a bitcoin from someone else who has one with local currency, I lower my risk of ruin from currency inflation by paying a price that I deem reasonable, the other guy gets cash which he could use to start a business or anything else that's inside his risk tolerance. No one lost in that scenario.
You could just use dollars, euros, or yuan instead. Which is what people currently do in that situation.
Or, be like the mobsters and take payment in goods like olive oil, stolen art, or drugs.
No longer true. I used to believe this as well, but I’ve been blown away by the work from Lightning Network [1]. Subsecond transactions that happen off the Bitcoin blockchain, scales beautifully.
This means that Bitcoin is a 0-sum game*, and a tremendous waste of resources. At least with gold mining we end up with a material that has important industrial use.
0-sum game: Meaning, in order for someone to profit with Bitcoin, someone has to take a loss.