Anything that is valuable to someone else can become valuable to me. "You like baseball cards? How you like this one?"
You don't have to believe that money is inherently valuable; you just have to know that it is valuable to others.
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Cryptocurrency Prices, Charts And Market Capitalizations | CoinMarketCap
The total market cap of crypto is $1.51T. Do you any of use have to believe that any of it is inherently valuable? No. It is obvious that it is enormously valuable to a substantial community of traders.
I think the rub is that we worry that others might somehow stop valuing crypto assets at some point in the future. So we look for reasons why a thing will remain valuable even after most people cease to value it. This is the quest for something to "back" a currency. We think, If the dollar loses value, the central bank ought promise to give me a certain chunk of gold for this note. If the bank does not back this thing, I can't believe it has real value. Of course the token value of currency so outstrips whatever "backing" value there may be when the gig is up, that the backing value is financially meaningless. If you ever have to exercise whatever redemption value there may be, you've already lost enormous token value. All that backing was really good for was some sort of emotional support for the belief that the currency has real value. It may be uncomfortable to accept that the insistence on some inherent, lasting value to "back up" the token is a wish to be satisfied with magical thinking. This is why I take an almost atheistic position that the essence of token value is no inherent value. Real money has no inherent value, it is pure token value.
But the way out of disbelief is to take a more pragmatic view. Money has value because it is useful. Through repeated experience I experience value using money. I work for money, I spend money, I borrow money, I pay back debt with money, I give money as a gift, I pay taxes with money, I receive money as an inheritance, and on and on. In all these things I don't really need to believe that money has real, intrinsic, and lasting value; it simply needs to work. If I pay off a loan with money, all that matter is that my debt is settled. I won't be compelled to pay the debt over again with some other token of value.
Indeed debt solves the problem of value. Borrower and lender contractually agree that debt may be settled with certain number of tokens. Mr Mselebende wants to borrow 500 USDT and agrees to pays 600 USDT 12 months later. The lender may be satisfied that pledging 0.005 BTC is sufficient collateral. Both USDT and BTC are cryptocurrencies. It does not matter that USDT is backed by US dollars, or that BTC is just bitcoin. What matters is that the lender is satisfied that 600 USDT settles the debt and in the even of default 0.005 BTC is a sufficient limit to loss. The lender also needs to believe that the crypto contract can be executed within the blockchain. That is, the computer code that operates the blockchain ultimately adjudicates the contract. There is in fact a lot of use value being created by such a system. Within that system USDT and BTC are tokens with define value. It could enable a person in the US lend money to an unknown person in DRC with reasonable expectation of profiting.
So when we contemplate whether $1.51T in crypto market cap has value, we might ask is anyone lending on this. Actually yes. In the US there are lenders accepting BTC as collateral. Few borrowers would want to borrow BTC because it has the potential to go up in value quite rapidly. Borrowing BTC is tantamount to shorting bitcoin! So USD or USDT is a better token for paying back loans sense the value is stable for both borrower and lender. But as to collateral the potential for BTC to gain considerable value over the life of loan is a positive thing for the lender. And conversely the risk that BTC could lose value exposes the lender to more risk in the loan. So for the lender to accept the terms of the loan, she must functionally believe BTC will hold sufficient value.
If $1.51T of crypto loses value, this means lenders who accept crypto as payment or collateral will lose value. Moreover, they are locked into the this risk for the duration of credit arrangement they write. The risk of losing value over a certain term of time should get priced into the interest rates under which credit with extended. Thus, we arrive at crypto yield curves. Yield curves reflect the present value of future payments in a given token. These are standard tools for doing financing in any currency. As cryptos evolve and scale up, such tools will be increasingly applied and reported. This will make cryptos more useful for financial operations. So in the end, token value is not an abstraction, but rather there is use value in tokens that are used for financial operations. To wit, this is how financiers put bread on the table.
Simply put, use is what makes money valuable. Indeed, money is technology.