Stablecoins, cryptocurrencies pegged to a stable value like the US dollar, were created with the promise of bringing the frictionless, border-crossing fluidity of Bitcoin to a form of digital money with far less volatility. That combination has proved to be wildly popular, rocketing the total value of stablecoin transactions since 2022 past even that of Bitcoin itself.It turns out, however, that as stablecoins have become popular among legitimate users over the past two years, they were even mor...