SEO is always the most important channel in general Digital marketing. This will help you in your long term campaign and drive organic traffic for your website, so I think SEO is never waste your time. In order to avoid waste your time, I think you need to prepare a good plan and budget on it. Doing SEO is not a thing that getting result instantly, in many cases it will take you 6 months - 12 months or even more to see the acceptable result.
Good luck to you,