I bought this for myself rather than a child. I wanted to pick up a little bit of Italian and purchased these Slangman audiobooks along with a regular Italian audiobook course. I honestly learned vocabulary and a little bit of syntax a great deal faster with these children's books than with the more expensive audiobook course. If they produced more of these titles, I would definitely purchase them.
The main advantage here is that you already know the story, and he mixes the Italian vocabulary and usage in with English. As you advance in levels, the stories gradually become more Italian than English. The tracks are pretty short so you can listen through them repeatedly as needed.
One drawback I find is that the audiobooks do not come with at least text copies of the physical books. You have to look up the words in a dictionary or translator to learn how to read and write them. Each of these books ought to come with some kind of written document which at the very least lists the vocabulary used.