Interesting visuals change the way in which people engage with a diagram. You can think of it as an aspect of storytelling. Personally I find my eyes much more likely to be drawn to these isometric diagrams, compared to a 2D equivalence. The 3D aspect draws my eyes in and keeps them there. So what's being added doesn't need to be raw information that changes the facts of a diagram, it can be an aid to processing. There's a reason that visual design is a thing.