Like most Star Wars movie novelizations it's essentially the movie in book form. While books adapted to movies often work well it typically isn't as interesting the other way around. But, I always read the Star Wars ones anyway just to get the bonus content and context to the universe.
The Rogue One novelization has a few scenes that either were never in the movie or were cut from it. It also fleshes out a lot of characters' internal thinking about events, which is something you almost never get in a movie.
My favorite part is probably the admin documents used to break up the story randomly. They give looks inside the building of the Death Star and inside the Rebellion. It's just tiny vignettes but they're great!
I wouldn't recommend this book to anyone who isn't Star Wars obsessed in the same way I am. But, I'm glad to have read it. I always like learning new things about this universe.