It's not nature, but everyone who already wears glasses knows what this is like. It's just part of my software by now.
If I physically move my head, nothing I am looking at is moving with me, i.e. the computer screen does not move to where I look.
The point is that you look through glasses, yet the Google Glass screen makes you focus on it, not through it, and hence it moves with your general head movement.
Or have I misunderstood what you said?
I still fail to see the point. Maybe because I never try to look at my own glasses...
edit: When I want to look over the rim of my glasses, I still move my head while looking up with my eyes, otherwise I wouldn't be able to look at what I was looking at before.