Creating an SEO campaign from scratch can be a daunting task. There are tons of components you need to consider.
Even if you get everything right, you know there won't be immediate gratification for your hard work. It'll take at least a few months to see your hard work pay off.
However, running an SEO campaign can force you to ensure everything on your website is technically correct and that there's enough structure for bots to crawl around on. It can also help align your whole marketing team in terms of keyword and content strategy.