This is a really good comment. But of course the problems in authentication and de-duplication are also different in that you care about adversarial false-positives much more once authentication is the goal. As I understand things, Worldcoin claims the retina scans won’t be used to control funds (or other services.) I am skeptical that many of those users will retain their non-biometric wallet credentials long-term, which will leave you with a database of biometric credentials that will have to be used for authentication if you want to use those credentials for anything important in the future.