Comment by LoganDark

> receiving a text message or email with a one-time code

This is less secure than pure username+password in principle because it gives an impression of greater security while actually delivering the important secret in plaintext. This can cause platforms to enable the higher trust features, or have additional confidence that someone is not an attacker, even when either one would be highly inappropriate.

TOTP does not have this problem since the secret is enrolled once by the account owner and then never communicated again, especially never helpfully to an attacker right when they need it.

> One use case is particularly intriguing to me. In principle, remote attestation can also be run in reverse, to verify that the server you connect to is not doing anything you don’t want it to be doing (such as stealing your credit card number, or keeping backups of the posts you delete). Sadly, to my knowledge, no major platform has ever implemented “reverse” remote attestation this way.

This is only possible if you've audited the code in order to approve it. In practice, this requires auditing the entire SBOM, manually, yourself, for every single platform release. Or deferring to someone else to do it. I expect this will never happen.