Same experience here - I scrolled up and down that page many times looking for a 'Demo' link, and it was only by chance that I clicked and dragged a block and realised "Oh, these block thingies are more than just decorative art!".

And to echo your other point - I am actually currently looking for a good drag and drop library for our web app. I would really like to see a more 'boring' demo which demonstrates some sort of Kanban board like functionality, dragging images or text blocks between boxes. I also want to see ability to restrict dropping or sorting etc. on a granular level.

The current 'demo' is cute, but not really translatable to my concept of what I want. I am more likely to dismiss this library as a games engine rather that something that could be used in an enterprise tool based on my experience to date.