Perhaps related to T8067 , but our use case may be slightly different.
One problem we are seeing is that - once an account has been approved - it is impossible to see who that account is.
So, for example: Someone registers the username "myname" with the e-mail "firstname.lastname@example.org". Once that username has been registered, there is no way for us -as administrators - to find out where the "myname" username comes from. This is a problem, because as an administrator you sometimes you want to follow up on a user's registration later.
Another use case is that we want to create a policy/project group that is limited to verified users in the ...@mycompany.com domain. Since we can't see the e-mails, though, we have no way of knowing whether "myname" is email@example.com or firstname.lastname@example.org. In practice, the only way we can currently do this kind of stuff is to send out an e-mail to everyone @mycompany.com and ask them to join manually - which doesn't really work.
Obviously, e-mails are not something we want to spread around, but it would be a great help if it were possible for administrators to see the e-mail addresses of users in the People interface; even better if they can be retrieved through conduit by users with admin credentials.