I get the impression that all the verbalisation/patter is for the benefit of the CVR? Either way, the b****rs will hang you after the accident!
Ditto the silent cockpit. However, I would say that it does take a certain amount brain-space even just commenting on the view and replying.
Therefore, it is inappropriate chat that is what the silent cockpit rule tries to eliminate.
For example, last night there was a fabulous view to be seen over London and the SE of England - with Bonfire Night fireworks etc. But we were so busy dealing with an overworked London ATC, a stack of aircraft recovering in a stream to the same airport, a wx-radar fault (for the isolated build-ups that there were), an anti-ice fault (ditto), as well as completing all the the normal verbiage to complete various phase-checklists, that not one comment was made about the panorama outside to window. Had either of us started talking about the weather/view then we could have easily overloaded things. I think that is the intention of a sterile cockpit - inappropriate chatter at the wrong time. Once again, we come back to basic airmanship - that the well-meaning but over-zealous try to implement by over-regulation. I don't believe it helps that much.