+1 from me for only using an email address. I was using commento: https://commento.io/ which is quite small and can be imported via one line of java script.
However having comments encourages people to leave low-effort responses like "good article, thanks". Email-only provides a kind of filter for low-effort replies.
That's exactly what I'm doing right now :). Email address is not exactly as encouraging to reach out as a simple comment box, but I've had a hunch that the small possible upside is just not worth the hassle, and your experience seems to confirm that. Thanks!