This idea came to me after my first on-call, when I had to quickly figure out what is going on in a distributed system of 200+ micro-services. That's why I focused on embedding documentation into a diagram and being able to zoom into the parts of a complex system as much as you can. So that you stay focused on the entire picture. The alternative is to jump between multiple Google Docs/Wiki/Readmes for multiple services and read tones of text.