That seems like a strange summary. A better one:
Everyone builds models about the world around them (Naur used "Theory" instead of "Model" but they're the same here). Not all models are as accurate as others, though they may be sufficient for many situations. The developers of a system (most likely) have the best model of how the system operates and is constructed. Operators have a separate model. Maintainers have a third model. By separating the initial developers, operators, and maintainers, and reducing communication to, primarily, the exchange of programming notation and documentation, three different models (at least) will be produced. Incorrect models lead to incorrect usage and incorrect maintenance activities.
If your programs are short-lived or very simple, this paper is of little utility to you. But if your programs are expected to live for a decade or more, or are very complex, the ideas here are more useful, probably critical to the longterm success of your enterprise.
I work (or have worked) on systems that were developed over 30 years ago. A lot of knowledge has been lost, and a lot of wheels get reinvented. Or components of the system go underutilized, or misused because of misunderstandings of how the system functions and was designed. The more successful projects have had people working on or with them for 10+ years. Without them, program modifications have usually been small (large changes were seen as untenable), complete rewrites (because no one understood it), or failures (long delays, maybe a working product at the end, often with one or more rewrites along the way).