But what is that new proposition
The book is written by julien bayle someone which (I assume) is not primary a programmer of electro guy and therefor I expect he describes the Arduino more from an Art point of view. What can it do, without reciting the technical specs. End result is far more important than optimal coding solutions etc. Mind you most artist know their requirements (WHAT) way better than most engineers. And yes, engineers know more about the HOW, (ying and yang in balance again pffff 
@Julien,
Please, correct me if I'm wrong in my above assumptions.