Even when effective, this is low leverage for conversion. However, it is high leverage for brand building and ideation.

People who know you through your comments really get to know you deeply via this method.

You can also flip the comment you just gave me into an article. "Some writers are always thinking about engagement. 3 tips I'd never think about if I weren't reading Medium."

Then it's

1. Comments.
2. Turning comments into articles.
3. ???