Allow IDs to have more than one verified email address.
Allow IDs to have one or more email addresses.
Allow all email addresses to be verified.
Provide UI to allow users to manage a list of email addresses, and their verification.
Return verified email array with user object.
Take, for example, a consultant who works for multiple clients; some clients choose to use the consultancy email address, some choose to assign them a client-specific address. They are still the same person, and should only have to identify themselves once whilst allowing for different contexts for that identity.
Another example is custom domains for emails, and now throw-away emails. One user may have many or even all addresses at a domain; perhaps again using them to split context, not ID.
I would want to be able to enable that one user to verify all their owned email addresses as theirs. This would be especially useful in using Auth0 when allowing tenants to automatically approve emails from certain domains (e.g. client domains) without users having to split their personality and create two identities.