I did get some good ideas for plot points in my current novel, so not a complete waste of time. But I feel like the way the prompts are structured and the events Alderson refers to in this book are very genre-specific, to either inspirational or women's lit, neither of which I have read. I write mystery, and sometimes fantasy or scifi, and I found it rather hard to find a way to apply these prompts to any genre other than mainstream.
There's also a lot of repetition, especially regarding the protagonist making mistakes, finding her true self (characters and readers are all referred to as "she" in this text, which only further supported my feeling of genre-specificity), overcoming obstacles, etc. Some prompts stole sentences from other prompts and felt nearly identical to other prompts despite being elsewhere in the book. I personally didn't find it at all helpful in the structuring of a novel, but I do think it's more helpful than generic prompt books, which might work for a drabble or a short story but not something as long and interconnected as a novel. Might work best for non-genre pieces.