I've seen feedback on here about having to manually link alias' to logins because the alias option doesn't save the URL, and how the prefix should be random instead of manually entered. Instead of fixing these issues, stop showing the alias and login options as the only two choices, and instead link straight to making a login. In login, when you click the email field, you're prompted to make an alias. This option saves the website URL and randomises the prefix. Moving the alias option out into the open of the login section would also help the situation.