A valid point, but even realistic metal isn't necessarily easy. The volumetrically diffuse reflections (that actually get sharper as geometry approaches them) you see of the robot prisoner's arms on some of the walls haven't been possible in real-time until only very recently, and is clearly a new feature Unity is showing off here.

What's most interesting to me, though, is the Unity logo at the end, which I assume must be showing off engine capabilities as well. It makes heavy use of sub-surface scattering, which is of critical importance to lifelike skin and faces.