the only way USD stablecoins are better than traditional fiat is by never being redeemed. when stablecoins are redeemed, the issuer uses traditional fiat rails to deposit central-bank-controlled funds into the redeemers fiat bank account. seems like something that only banks and those without access to USD would be interested. the latter group definitely matters, but they're just expanding the network effects of USD. stablecoins are another abstraction of fiat, a better paypal/venmo/etc.