Such a ridiculous setting

Why bind accounts only based on email? When the email is stolen by hackers and cannot log in, the second verification method (mobile phone number) cannot be used to confirm identity, allowing the user to change the bound email address. 

Question: If my email is stolen by a hacker and cannot be logged in, my account will be unable to reset the password or change the bound email address for the rest of its life. All server transfers will also require the bound email for authentication... Then What does the mobile phone number I bind do? 

Email is an important piece of information about your company? Phone number is not? Any computer can produce hundreds of emails. Not so with phone numbers