SEO and digital marketing are not in competition but rather complement each other. You need SEO for organic traffic, you need Digital Marketing for Direct Traffic, Paid Traffic, Referral Traffic, etc. If you are heavily dependent on SEO, and omit digital marketing, you might not be very successful. SEO eliminates the need for excessive spending on digiytal marketing for traffic and sales. While ad spending is necessary, SEO generally offers a cost-effective approach compared to advertising. Interestingly, if you are doing digital marketing social media and have managed to grow a lot of followers, you can get more traffic than SEO.