I have no idea. This did not happen to me when I signed up.
Personally, I would prefer the option to not have to give an email address to sign up. All the email address providers seem to require you to either give your phone number (personally-identifying information) or ANOTHER email address which likewise has to be created with a phone number or another email address. If it is difficult to create an anonymous email address, it is difficult to have discussion on this forum in an anonymous fashion.