We didn't want too many fake accounts. We didn't ask for phone numbers. It's very easy to get a burner email, in case someone wanted to avoid giving the main email. Burner phone numbers are harder.

Also, an important use is password and username recovery. We even got password or username request 30 minutes after signup! They had quiz to solve if they want to help during studding and it's good to track them.

We had a lot of wrong emails, in particular it was common someone@yahoo.com instead of someone@yahoo.com.ar because Yahoo! offer both options. Also someone@gmail.com.ar that does not exist, but that never stop users.

(If it help, we never asked to confirm the email again after the registration.)

how do you prevent malicious use intentionally signing up someone else without verification? and how do you verify your own email if you are not technically competent enough to know how to spell your email correctly? (probably not an issue for students, but just seeing stories here on hackernews about people receiving emails not meant for them shows that this is an issue)