Hardware instancing is definitely interesting.

I was talking more about groups and lights - I would find it very useful, to say lay down a group of blue floor lights, all instances of one another, and adjust all by changing one.

I rely on this a lot in Max and other 3D all of the time for laying out lights, and models.

Or decide, I want to use a different wall lamp, change one in wed, and they all change - that kind of thing.