We are requiring google sign in only to collect feedback from our users regarding improving the extension. Also, to manage subscription to premium features in the coming versions.

We are working on a new version now to make the extension doesn't require any login for a week to resolve this issue. So, if the user likes the extension will keep it and if not they can just uninstall it without worrying about sharing their email address with us

It doesn't. I assume your extension tries to use Chrome's connection to the user's Google account, but I'm not logged into my Google account. Mostly because I only use Chrome for web development/testing, but I was curious about how the features would work for me. Of course that makes me a rather irrelevant minority of the userbase.