External users choosing to restrict their profile visibility settings, especially email, will:

1. Confuse other users when the external users share the same public name.
2. Prevent other users from
   1. Contacting them via email or chat.
   2. Using the email address domain to confirm the association of an external user to a company.
   3. Using the email address as a confirmation for confusing public names.

Suggestion

Provide an option for org admins to require all users (inc. external) to expose email addresses within the scope of their organization's products. This would provide all product users with the ability to see the emails of external users they are collaborating with on different products.