I would like to use the site without logging in. A Google account is required to use the site (pastcasting, calibration, estimation game). This is an unnecessary hurdle. Not everyone has or wants a Google account. From a technical point of view everything could work without logging in (using cookies or localstorage for persistent state) and I would be fine with not being able to show up on the leaderboards.
I understand that the Google login makes it easier for you to make the site and this might be an unreasonable request.