When you register your account with Pi Network. You can verify your identity with either facebook or phone number.
Facebook verify - Facebook login (optional)
Pi only uses your facebook login to authenticate you as a person, not a bot. Pi only asks for your name and email from Facebook, and cannot post anything to your Facebook profile.
Note: If you verify with facebook, you are automatic verified. You will see an N/A next to your phone verification. You are set phone verify is not needed.
Why my phone number is needed?
Because we are distributing real digital coins. Pi needs to validate that all of its members are real human.
New guidelines from Core team
The official stance is that Pioneers don’t need to do verification with Facebook or phone.
They can mine and maintain the Pi mined even if they’re unverified, but members verified through either Facebook or Phone number will have more credibility in the network, e.g. eligible to certain chats and giving more confidence to people when others add members to their security circles.
The warning messages in the app are not consistent with the official stance and need to be changed.