Everyone who has an iPhone uses iMessage as a main communication app. Nobody bothers to replace their default SMS client and literally all banks, institutions, 2FA and key communications rely on sms to work.
Receiving a second factor is hardly communication. Nobody sends a thank you SMS back.
Receiving a second factor is hardly communication. Nobody sends a thank you SMS back.
Heck, I get 2fa WhatsApp messages these days.
Except it is
By a very strict definition: Yes.
By anything that matters in the context of this: No.