I don’t know about you, but I skip around a lot when I’m writing. In other words, I don’t start out with chapter 1 and continue on straight through until I type “The End.” This is for numerous reasons. One is that I write using multiple viewpoints and sometimes it’s easier to follow that person through several chapters. Another is that I tend to write in layers. I don’t conceive a story in its detail all at once, but go back as other things come to me, whether it’s tweaking dialog or improving a description.
Needless to say, this can get tedious. I’m currently dealing with a 141K word WIP and jumping around to find the right place can be a real nuisance. One way to get around this is by bookmarking certain scenes or chapters so I can get there more quickly. I always seem to be short on time, so every trick that saves a few moments helps.
One thing to remember, however, is you need to remove them before submitting it for ebook or print format. The coding can really honk up the final version, plus the bookmarks may not be in places that make sense to anyone but you, anyway.