The other two downsides are: Some people may chose not to have their email account on the phone. Personally I don't want to carry around access to my main email at all times (the same goes for access to my main bank account, BTW.)

Also, email delivery sometimes takes a very long time, it can be minutes, if you rely on email forwarding to protect your main email address.

Auth apps are better for 2FA, at least for me.

If it weren't for SMS 2FA, I wouldn't carry around my "phone" number on my phone. I'd just use data-only SIM cards.

Email is absolutely worse than SMS

In what way is email worse than SMS ?

First of all it's not two factor. Which is the entire point of two factor authentication. Just do a little bit of thinking on this, you'll get it

How is SMS two factor when email is not ?

Separate from that, it is not productive for you to tell me to think about it more -- for all you know I've implemented two factor authentication in various forms for decades (from OPIE when I worked at NRL to Smartcards within DOD to Passkeys currently). What would be more productive is to get more insight into what you're thinking

If you have access to somebody's email you can just click reset password and then click the "2FA" in their email and then you have access to their account

Does that happen with SMS? Hmm...

The same situation seems to be true of SMS, if you have gained access to their account then you can use that to perform 2FA as well. In this situation, it doesn't seem to be significantly different in terms of security.

To answer your question on whether or not people access other people's SMS accounts -- yes! That's one reason it's not recommended any longer. Additionally, there's often less security possible for ones SMS account versus ones email account.

...

You would have to get access to their email and SMS to perform a password reset and get past 2FA. If you are saying you could do a SIM swap attack simply by having access to their email I think that is not that practical at all.

> To answer your question on whether or not people access other people's SMS accounts -- yes!

What? I never asked that? What are you even talking about?

It's really unclear to me why you think that email would be involved in any other capacity than 2FA in this scenario.

Are you imagining that email is used in some other additional way in the authentication process, such as account recovery ?

You've never done a password reset? That goes to your email. If your 2FA is over email too then that isn't 2FA. Because you only need the email to take over an entire account

So I see the problem now, your model includes a hidden assumption that password resets go to email -- this is not always the case.