Some comments to what I post contain questions to help that person understand what I wrote about. I then re-read my work and often discover how I could have worded things differently or what needed to be added/deleted for things to make more sense. It improves my ability to get my point across so the articles help other people. That can then be applied to providing better descriptions or explanations in my novels and subsequent articles.
Even without using blatant self-promotion, writing articles may lead people to want to know more about me and that leads to my books.
**Please note that I'm not asking anyone to check out my books. I'm simply being honest with my answer.