Why did the glory of the king use his original mobile phone to send text messages when logging in?

Landing in the glory of the king, because of security needs, requires SMS authentication.

2.

SMS authentication is a measure to protect the security of individual user account data. Because now the mobile phone number is a real-name registration system, use the verification code to prove that it is your own operation to prevent others from logging into your account. This is a common authentication method now.