Researcher Jane Manchun Wong found that Facebook is working on facial scans called “facial recognition-based identity verification.” It would ask users to upload a selfie of them looking in different directions before they can access their account.
On that same screen and later in the actual video selfie process, Facebook notes that “no one else will see” the video selfie you submit to them and says the video will be “deleted 30 days after your identity is confirmed.”
Deleted after 30 days. Based on Facebook’s past actions we can safely assume it will do the exact opposite. There’s not much room for giving them the benefit of the doubt.