The only danger that I read into the ideas explained here, is that a novice writer might come away from this article thinking that the meaning should be in the text (the dialogue), rather than meaning inferred from subtext.
For instance the exclusive dialogue example could be appropriate depending on the previous scene, the character arcs and how well the audience is empathising with the protaganist. Something could be happening in the scene from which we infer meaning that isn’t in the dialogue. Raymond Carver comes to mind.