The styling and formatting helps users find information quickly if they want to skip across the article.

Formatting also helps with making an article look "like quality" and the user will think the author has spent some extra time to make the article very presentable. This in turn helps with keeping bounce rates low as the user is more inclined to stay and read the article.

I mostly use H1 or H2 for the most part. H2 mostly for the other sections. The headers after H3 is a bit much for short articles, perhaps better use for long written pieces.