As a parent, my answer is ABSOLUTELY! With my daughter, I had a challenge transitioning her from single words to sentences in books. I suspect that she was intimidated by all of the words in the easy readers were using (not BrillKids) or for whatever reason, she struggled with reading books initially versus flashcards. She could read any flashcard you put in front of her and she liked ME reading to HER, but I had to get creative to get her over that hump. Since the birth of my son, the storybooks came out and I have never had ANY issue transitioning him to books at all. It was so natural and there was simply no issue. All of the font is so clear and the words are familiar from the LR lessons, the illustrations just delight him. Even my daughter will flip through them for fun even tho she's older and they are far to simple for her.
I would look for some of the other items second hand on the Second Hand Board to save money to be able to purchase these books. There are some up close videos of my son reading these books on my youtube channel located in my signature below if you want to see the "inside." The book shown on the main page of my daughter reading gives an example of some of the easy readers I started her on. They were much more difficult! I love those books too (the preschool prep readers as shown with my daughter) but they are so difficult in comparison to the BK storybooks when used to transition kids from flashcards to books. In USD, the difference is about $50 and at 25 books, that comes out to around $2 a book. A small tool that can make a big difference in the success of your child IMO.
The short answer? YES, YES, YES!
http://forum.brillkids.com/sell-plus-swap/