This contribution mechanism allows us to split our documentation across concerns, free from any structural constraint due to your implementation language.

This improves the readability of your doc, as your reader will be able to have a step by step reading. This also improves the readability of your code , as you can focus on the parts of the code that fulfill the concern that interests you right now.

Let's take a concrete example. On one side, you've got the Intent document I use to document the Intent code. On the other side, you've got Intent code itself.
In a first section, that gives a very high-level overview of the synchronization, I do not enter into technical details, focusing on describing what is synchronization (defining requirements and high-level architecture).