You can add value through Blog posts to your visitors, by talking about topics that you are knowledgeable and providing content that they find useful, something that benefits them.
So when you write your blogs, you are writing about content that is associated with your website. Creating content with keywords and broad strokes about what search terms people might be searching.
Also if you write great content, you could have other websites refer to your blog about a certain content and then that create backlinks.
Long tail Keywords
The very basic explanation is that it’s an additional area to bake keywords into your site when done properly. Things like long-tail keywords are much easier to get traffic from and blog posts are probably the easiest way to get them to your site without seeming spammy.
Let’s say you write a post like “How to Pick the Right Detailing Service for Your Car” and include things like service types, products, and all sorts of good process stuff.
Visitors like this because perhaps it explains the difference between a basic detail and a full-blown paint correction and why they might need a certain service and not another.
Blogging is not going to magically provide more “SEO juice”. You don’t need a “blog”. Google could care less if a site has one or not. You can just create pages about the topics you want to cover and you will have the same results.