On the other hand, you can't type your fingerprint into a random link that you receive in your email. I think modern devices that use biometrics to unlock a se

On the other hand, you can't type your fingerprint into a random link that you receive in your email. I think modern devices that use biometrics to unlock a secret key are different from the old-school case of biometric authentication. If someone is storing a picture of your fingerprint, then of course they can replay that to impersonate you. But that's not what TouchID is doing -- it's just a chip that will only give up the private key if it detects your fingerprint. You have to have physical access to that chip, and a finger analog that will fool the chip into giving up the secret key, and then you can use that key to compromise things. But if you detect that, you just revoke the key, get a new device, and are good to go. I don't have a great analysis for sudo. You want root on MacOS to do something like install a long-term compromise. Your regular user account already has your GMail session cookie and bank information, so sudo isn't really good for anything else; if you leave your unlocked laptop around somewhere, your Internet life is over. But if someone physically steals your finger so they can gain access to sudo and install a keylogger or something, you already know you're compromised -- your laptop and finger are gone, so you know something's up, defeating the purpose of a long-term compromise. This attack can't be done remotely; if someone sshs to your laptop and wants to sudo, they can't just take a picture of your fingerprint and upload it... they have to physically touch the sensor on your laptop. Overall, I think biometrics like TouchID / FaceID / U2F / WebAuthn are strictly better than passwords. They are super convenient. They can be revoked. They can't be phished. That's a huge win over passwords.