In a column for the New York times in 2018, Paul Krugman wrote,

To some extent gold is in a similar situation. Most gold just sits there, possessing value because people believe it possesses value. But gold does have real-world uses, both for jewelry and for things like filling teeth, that provide a weak but real tether to the real economy.

Cryptocurrencies, by contrast, have no backstop, no tether to reality. Their value depends entirely on self-fulfilling expectations – which means that total collapse is a real possibility. If speculators were to have a collective moment of doubt, suddenly fearing that Bitcoins were worthless, well, Bitcoins would become worthless.

I think it’s more likely than not, partly because of the gap between the messianic rhetoric of crypto and the much more mundane real possibilities. That is, there might be a potential equilibrium in which Bitcoin (although probably not other cryptocurrencies) remain in use mainly for black market transactions and tax evasion, but that equilibrium, if it exists, would be hard to get to from here: once the dream of a blockchained future dies, the disappointment will probably collapse the whole thing.