I found this article by Kristi Hines on “Why Static Websites Need a Blog”
Most static website owners have found that adding a blog section to their website helps in a variety of ways. As mentioned above, a blog offers new content for visitors to discover on each visit. A blog also gives visitors a reason to subscribe, so they receive updates when the blog publishes a new post.
The promise of new content is the reason maintaining a blog is essential, even for those with static business or niche websites. If someone visits a static website and has no need for the products or information, he or she will have no reason to return. If a visitor sees the promise of new content in the form of new blog posts, he or she will have reason to return, which could lead to future product sales and information consumption.