Recently I spoke with a man who is a highly successful business consultant. He is very accomplished: he has a PhD, has written four books with another in the works, has been involved in various capacities in many professional organizations, has started and sold businesses and is on the board of several more.
Every time you create a blog post you're creating a new/unique page online (on the internet, across search engines). This means that you're increasing your chances of ranking in search results, having other websites link to you, and your post/blog being shared on social media. All of this results in new traffic to your site.