The article, which I liked, is very end user-oriented, but I think that the ability of other programmers to interact with your conceptual models is just as important. Other people have to work with your code, and their ability to develop new features will very much depend on how easily they can work with your conceptual models. Onboarding programming hires into a poorly organized conceptual model will be a mess, and disheartening to the new person.

Good conceptual models can be extended, interacted with, and built upon, and that which an end user may regard as a "feature," including features not yet thought of, flow naturally from the best models. So there are some knock-on benefits to the end user from good conceptual models under the hood, even if the end user doesn't see them or have an opinion about how intuitive they are.