"J.K. Rowling herself once said that Harry Potter and the Cursed Child needed to be a play, rather than a book, to give full life to her creative vision. Many of the play's reviewers were impressed by the staging and tricks that brought the magic to life before the audience's eyes. No script is ever going to be able to offer those things. Indeed, anyone who reads script before seeing the play will find their brows twisted in disbelief at some of the stage directions and wonder how on earth such a thing would be possible."
Yes, it is NOTa book, it is a script, and we have to treat this work as one. It was not written by J.K. Rowling, as many people may assume. This book would have received much more praise and love if the readers had known the mentioned above facts straight from the beginning.
Is it worth reading it then? If it's your first experience with the wizarding world of Harry, you should definitely leave this book on the shelf in the bookstore and grab and devour the first 7 books about Mr.Potter. Otherwise, "the cursed child" won't make any sense to you at all.
All in all, it was great to enter yet once again this beautiful magical world, escape from reality, join the great company of my favourite childhood characters and see this story from a different angle.