Yeah, agreed. But again I'm not arguing that SMS is the best second factor, I'm arguing that (used correctly) it's better than no second factor, which is what i

Yeah, agreed. But again I'm not arguing that SMS is the best second factor, I'm arguing that (used correctly) it's better than no second factor, which is what it's actually competing with in the real world. Generally, I think services should offer TOTP, email, and SMS, and strongly encourage TOTP. But not offering SMS just means some segment of customers won't have a second factor at all.