I think it is a really great tool. It makes learning more fun than a typical quiz and the fact that it provides instant feedback is great for me as I need to know what to plan ahead. I would recommend changing the color of the app as it is a little sad and making it more bright and happy, which will make it more interesting for children.
How I Use It
I would use this resource in my teaching to create polls on the previous topics and to assess their knowledge on the topic instead of having to take a quiz.