if cryptos fall back to zero (they have already lost 80% of their value, or $750 billion), their mining will have represented one of the most fantastic waste of energy in modern history. The only "objective" value associated with them is the energy cost of their extraction... Cryptomos will not leave any material traces in the world heritage (because even an abandoned industrial wasteland is a testimony to our past, structural metal can be recycled, etc.).

Cryptos could have just increased the pollution of the planet without ever having been used for anything to protect it.

But taxing crypto-miners is impossible...