You need an eye and a brain for design. There are many business owners who have a good eye for design. It’s a valuable talent to have, but just because you have an eye for design doesn’t mean you have the skills to implement it as part of your marketing strategy.
Being a professional graphic designer means going to four years of school to perfect one’s skills. It isn’t a skill set you can just pick up off-hand, although some people do have more of a knack for it than others.