> where the only investment opportunity is as an economically corrosive synthetic hedge against all productive assets
Elementary finance theory (quoting Tobin's Separation Theorem here) argues that portfolios should be comprised of some weight of nearly all if not all of the available securities, as even assets with poor expected returns can be useful elements of a portfolio in order to improve diversification within the portfolio and reduce the portfolio's risk. Dumb money should be hedged against productive assets.
Is crypto a productive asset? The author's argument rests on the presumption of no. People who use cryptocurrency to cheapen and hurry the process of transferring capital across borders, compared to wire transfers, would say yes. Leave aside that international wire transfers could be sped up and made cheaper with a centralized authority in theory, the fact remains that in reality the fees are what they are. There's additional early work in using NFTs to deliver real-world benefits, where the issuer of the NFT derives value in outsourcing the tracking of who holds the rights to the real-world benefits to the miners propping up the backing blockchain rather than running their own centralized system. Is that enough value to justify the costs? Maybe. Hard to say. Too early to tell.