Firefox Sync: Use 2-step authentication instead of email...

[Dutchglory]

Firefox Sync use 2-step authentication instead of annoying email.
2-step authentication is much safer and faster, email can be hacked...

see images..

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[Cyc]

Everything can be hacked but TOTP as second factor is already implemented. I think you're using your Google account to sign in, instrad of an email address and the 2FA on the screenshot is Google's.