Having an interactive tech demo like the Japanese garden is fine for it's purpose, showing the capacity of the system. Some (me included) might like to have it available for different reasons: decorative, relaxing, etc. We have similar applications in the WiiWare service like those interactive aquariums or decorative fireplaces.
But why go into all these efforts if a trailer is as effective to show what the game is like. I'd rather have a demo. For example the Japanese garden demo, you could be able to walk around the lake at your own leasure, switch to the bird and fly around the scenery, have a free camera to move around or your interactive trailer.







