People can also use software browser-plugin authenticators, or software solutions provided by their operating systems. Even software anchored webauthn still stops far more threats than TOTP or SMS. That said few would need that fallback as TouchID or Chromebook authenticators or Windows Hello all work great too.
1Password is a centralized and proprietary database system that leaks all secrets to system memory every time you use one. Why would you want that to manage webauthn secrets for you? You just tap your webauthn device when prompted. No third party control required.