Because if you want to beat a pitcher at his best, you want to beat him at your best. Bunting is cheap in the 8th and 9th inning in a no-hitter or perfect game situation.
I'm not so sure about that. If it was easy to bunt for a base hit, everyone would do it, wouldn't they? And in reality it depends on the circumstances. And if you're down by 1 or 2 runs, isn't it the job of the hitter to get on base any way you can? Especially if you're the tying run or bringing the tying run to the plate. The point is to win the game.
If the Yanks are being no hit by Beckett in the 8th and are down 1 run, you wouldn't want Gardner to bunt and try to get on?