My first impression is that this book takes you by the hand and guides your writing or something. I feel that is ultimately counter to why I personally journal.
I want as little between me and my thoughts as possible. Only a pen. It's between me and myself to sort.
I personally haven’t tried it but looking at the website it seems like a good journal for those who may have trouble starting a journal entry or just want some sort of theme going. It wouldn’t work for me since I tend to just write long winded paragraphs about anything. Maybe you can use it as a baseline in how you want to structure a physical journal and add more features to it, if you want to ever transition into a physical notebook and not pay for the premium version.