In an effort to make your website easier to navigate for the search engines, SEO simultaneously helps to make your website more navigable for users as well.
SEO is Good for Business Visibility and Branding
When people search for your products and services, you obviously want to appear as high in the search engine rankings as possible, but the reasons for this are more than just because you want them to click through to your website. In fact, there is a certain amount of value in simply appearing in search results for terms directly related to your business. For instance, most searchers don't just simply search once, click on some websites, and be done with it. Instead, they search, click on some websites, edit their search terms, search again, click on some websites, further hone their search terms, search again, and so on.