Using phone number as an example of private information is pretty hilarious. Remember when the phone company used to literally print your name and phone number

Using phone number as an example of private information is pretty hilarious. Remember when the phone company used to literally print your name and phone number in a book and send it to everyone in your town? Man, their security was terrible! But it works perfectly fine as a two-factor auth mechanism to prove that whoever setup the account is the same person trying to log into it at some later time.