It's closer to the later, as it is meant to show the outcome is inescapable. It was originally missing from the game when first released, but I realized that players are often encouraged in other games to try to prevent the inevitable, and some didn't like the explanation that "the characters had no way of knowing."
It technically "rewards" the player with the spoils of battle and alternate dialog, and it "punishes" them as I feel like it is surprising and a bit cruel, but more than anything, I classify it more as a small secret or oddity. It's meant to signal "Hey, I know you don't want this to happen, but it's going to happen. You cannot change this."