I get your argument, but I liked it! Something about isolating each segment makes it feel more readable. Perhaps in an ideal world every article like this would allow the reader to switch between "slideshow" and "single page" view, since the same content would work for both.
Yes, it would be good. However I guess even simple show/hide chapters/sections also would do good work. It could be something similar to foldable directories or code fragments in code editors (for example VS Code has this feature).