@riskybusiness So here is my take on the core problems with it:

1. For the average user SMS 2FA is enough of a security measure to keep them safe.
2. There is no denying that SMS 2FA is easier than Authenticator apps or YubiKeys (this is a design problem that should be addressed, but my Mom doesn’t even have to open another app for SMS 2FA, and that’s a low enough barrier for her to use it).
3. According to the Twitter reports more than 75% of users (I believe it was 75% of users with 2FA, need to verify that) use SMS for their 2FA needs, and many of these simply aren’t going to switch.
4. Twitter is leaving SMS 2FA for the users who are most likely to have a threat model that requires the use of a stronger 2FA option