> For example, a conceptual diagram that complements the actual "as implemented" diagram. One is a big of a "here's what we were thinking" and the other is "here's how we translated that to actual architecture".

It maybe could have been clearer in the article, but the intent wasn't to discourage "here's what we were thinking"-style whiteboard diagrams. Those absolutely have their place. The article is trying to discourage people from making "here is how Kubernetes works" or "here is how microservices work" diagrams, since you can easily find those online.