A CEO just needs to make sure that stuff gets done; doing it personally is just one of the ways to get there. (And not a particularly scalable one.)
For Apple it probably made sense, because the whole company's image and reputation is built on that stick.
But eg for a toilet paper manufacturer or a producer of fighter jets, the CEO shouldn't spend too much time personally testing the products.
For the former, because presumably the product doesn't change that often.
For the latter, because there's not even a single 'user' of the product. The experience of the huge ground crew (with various specialised roles) is just as important as the experience of the guy in the cockpit, etc. No CEO, and actually no single person on earth, has the expertise to judge all of these aspects of use by themselves.
That doesn't mean the experience of the users is irrelevant. Just the opposite! But the CEO will have to intelligently delegate.
