@tomterp on the last part, not necessarily true because the margin can affect strategy in game.
It's an interesting point. Obviously a walk off grand slam to win by 4 is no better than winning by 1 (except from an individual player's or gambler's perspective.) However, while seemingly useless beyond the psychological lift of finally scoring, the bombs hit by Nix and Gomes could still have an impact. The situation changed pushing Gibson to bring in Putz. Yes, in this case, he was warmed up anyway, and was likely (as it turned out anyway) to be finished within a couple of pitches. But the same type of situation in the future could create a situation where the closer needs to come in and work an extra day than expected. And while that wouldn't necessarily change the outcome of the current game, it could impact availability, performance, and outcome of subsequent games.
It's a classic case of, "you never know."
It's sort of like the case where Gomes's bobbled ball allowed Upton to score without a play. He may have scored anyway. And even if he was held at 3B, people look at the subsequent hit and say he would have scored their anyway too. But you never know. Perhaps the pitching and the approach at the plate are different there if he is at 3B, and the result is different. Every play made or not has some potential impact. And you don't want to not score runs simply because they don't impact the final outcome.