Because in a book you can go back anywhere you want at any time. Videogames are the only medium in which that is sometimes made difficult for no apparent reason. Because you can create your own archive of the autosaves outside of the game. It just makes it more annoying.
That can range from a simple I’d like to see/do X again to a more involved choosing the other option.
Being able to start any levels/chapters once you finished it is a reasonable compromise but comparatively still pretty annoying.
Ideally you’d have the chapter thing (so you can ignore it) PLUS your own saves (i.e., bookmarks).
The mere, what was it, ~10? save slots in Thimbleweed Park were its biggest technical flaw imo. I (almost) never want to overwrite anything. I only want to add.