WebAuthn uses FIDO Security keys, relatively cheap USB or Bluetooth devices or sometimes just a built-in feature of a smartphone, to authenticate. They are Something-You-Have, but the WebAuthn protocol also offers:
* Optionally a mode where you give the FIDO key a PIN (Something-You-Know) or biometric input (Something-You-Are) to do all the authentication locally
* Phishing proof - there's no decision about whether this is really your bank. WebAuthn is completely happy to log you into https://fake.bank.phishingsite.example/ but the credentials are useless to the crooks who own that site because they won't work on https://your.actual.bank.example/ even if the crooks got the logo just exactly right and wrote a very convincing pleading email from your bank saying they definitely need you to go to the fake bank site.