If you chose the email option instead of “sign in with Google”, the server will probably use that email address to send you a login link. This is pretty standard for any web service, even blogs, where users can create accounts.
Sure, the login and sign up process is standard. But it's not typical to provide no information as to who is operating the site, or what the site does. Do those things appear in your browser?
I only see a title, a sign up link, and some celebrity photos.
If you chose the email option instead of “sign in with Google”, the server will probably use that email address to send you a login link. This is pretty standard for any web service, even blogs, where users can create accounts.