All value operates on the "prove me wrong" principle.
When someone overvalues any good they are trying to sell, they can easily be proven wrong by competitors in the same market.
However, when that good is scarce, it is much more difficult to prove a seller's valuation wrong by finding the same good for a lower cost.
If a good is scarce but is not desirable, resulting in a lack of demand, the seller's valuation will be proven wrong simply from no one wanting to buy what they are selling, regardless of its scarcity.
I hodl #Bitcoin because I believe it is worth much more than what people are currently willing to part with it for, and I am challenging everyone to prove me wrong over a period of decades, rather than days, weeks, months, or years.