Presumably your complaint is that cryptocurrencies don't have "economic value", but what theory of value are you using to decide that?

Exchange theory of value says that a commodity has two values: a use value (what it can do for you outside of the market) and an exchange value (what others will give you for it in the market).

I think it'd be correct to say that cryptocurrency has no use value, but it obviously does have economic value. And it's far from the only asset with these characteristics.

If someone is willing to pay me interest to use my belongings to generate loans, then those belongings have a value. If you think that banking has value, then banks who use the blockchain ecosystem to provide banking services are generating value, correct? The question I would then ask, on the spectrum of risk, value generated, and trust, do these blockchain based financial institutions offer a complementary or competing product vs traditional banking. As of thus year, I would say yeah. I am close to converting a chunk of savings to stable coin abd putting it with a insurance backed blockchain financial institution, and am looking to ear a much higher apy than a traditional bank.

Simple. Gold is an asset that is not used as currency but provides the holder with certain desired benefits and the asset can be liquidated if needed. Crypto is similar in that it prodives a financial vehicle that posesses certain properties. Im not saying they should all be thought of as digital gold but that lile gold, they provide value not only in thier price tag but in some inherent property that provides value to the user (this property varies wildly from crypto to crypto and is what makes each project distinct and unique.