Storing emails would be a convenient way to send the link if the user did not send it from the registration page or lost it in the meantime. As a user I would love seeing this kind of identification and would probably set a email account only used to recover links and avoid sharing my main email account.
Nice work by the way.
Good point, but for something done in 3 days I didn't want to risk having left some SQL injection somewhere somehow and leaking people's email.