Even if the business owner doesn't plan to do their own SEO, it's still important for them to at least be familiar with the general concepts and best practices. Otherwise, it's easy for an unscrupulous "SEO expert" to scam them and sell them worthless "services" that won't help their business at all.
I recently read a news story about a bookkeeper who stole hundreds of thousands of dollars from her small-business clients. She was able to get away with it for a long time because the business owners didn't know anything about basic financial controls and just turned over control of their bank accounts and financial records to her. If they had taken even a few hours to educate themselves about the appropriate division of duties to maintain adequate controls, they would have been in a much better position to protect themselves.
Just so, a business owner who wants to hire someone to optimize their site but doesn't take even an afternoon to educate him/herself about the basics of SEO risks losing a lot of money and wasting a lot of time dealing with so-called "experts" whose tactics won't do anything to help their business.
It isn't necessary to be an expert yourself, but if you're going to go into business it will pay to learn at least the basics of all aspects of what it takes to operate, promote and grow your business.