I find the format of a book a bit puzzling for what seems to be a mixture of technical documentation, introductory material, and educational material, all in on

I find the format of a book a bit puzzling for what seems to be a mixture of technical documentation, introductory material, and educational material, all in one place. What exactly is the audience of this book? Why is it not just part of Deno docs? Why does it seems torn between multiple objectives? Surely this will just become outdated as Deno changes over time, which it will as a fairly new project.