Loved it to finally read this book, after having seen the movie twice! 
It being a screenplay is still new to me, as Cursed Child was the only other book in this format. But it actually helped me understand the story even better than I already did.

As someone who is interested in screen and play writing, this was a good read as you can learn from it. However, as it is literally a play by play of the movie it can get boring and tedious if you've already seen it.

I would say that if you are interested as well in writing script, or even just curious about how they look and work, read it. If it is not something that calls your attention, if you get easily bored, or expect the script to contain more scenes or extra information about the movie, I would recommend that you have these things in mind when picking up this "book".