These giants are obviously rude, messy, lack manners, and appear to have been protesting any type of grooming rituals such as a bath. Beatrix helps the giants change their ways and changes their lives in the process. They are no longer the rude giants reeking havoc on the town because they have become kind neighbors who model appropriate behaviors. Is that a lesson I sense? Yes. Definitely.
Clearly, the book is promoting positive behaviors in a unique way. Instead of a story about children who are messy and refuse to take baths that are rude, the author decides to use characters that are not your everyday people. Giants. Who wants to read a book about rude kids who learn a lesson in hygiene? Maybe some. Who wants to read a book about rude GIANTS who make a huge transformation? A lot more people I would bet.
The illustrations are vivid. The bright colors combined with the facial expressions of the giants as well as attention to detail make for a very visually appealing book. You can almost grasp the story based on the pictures alone, and that is a hard thing to accomplish.
I would recommend this book to anyone wanting to show the importance of appropriate behaviors regarding cleanliness without coming across as giving a lesson (boring). After all, giants are imaginative and great characters.