The fascination with cryptocurrencies shows no sign of fading. With the passage of the Guiding and Establishing National Innovation for US Stablecoins (Genius) Act in July, US lawmakers added to the sense that crypto is here to stay. But an uncomfortable issue remains unresolved: are cryptocurrencies a genuine innovation capable of serving the common good, or a speculative threat to financial and social stability? Not all cryptocurrencies are alike. Unbacked ones, such as bitcoin or Ethereum,...