I definitely remember seeing a vid where somebody took a fresh vertical attack that killed with no DI and didn't use the key, and then took the same (also fresh, same percent obviously) vertical attack with no DI using the key and it did not kill. But I will certainly look again.
Fast falling any aerial with any character will decrease the vertical component of your knockback by an amount proportional to your fast fall speed. It doesn't matter what aerial it is (falling aerials like the key are not better). However, with Game & Watch, you want to be able to use the bucket as soon as possible after your aerial, and the key lasts much longer than the fish bowl, so it's strictly worse than the fish bowl. (I didn't mean it was worse than doing nothing; it's better than doing nothing.)














