The one thing I'll add is that it's a spectrum, not a binary.

Duff's example is just closer to the center.

There's also the factor of broken rules to consider. CaS functions because that Gentleman's Agreement keeps the DM and the players from digging those outside edges where the game-mechanic physical laws break down. CaW, on the other hand, may either exploit those boundary spaces, or the DM and players might try to patch them pre-game as best they can. (Even in CaW, the players may expect a good challenge and not rocks-fall-everyone-dies level DM BS.)