Knives are not particularly aerodynamically stable. (Not these, anyway.) They need some spin to avoid tumbling erratically. Nobody cares which point on a baseb

Knives are not particularly aerodynamically stable. (Not these, anyway.) They need some spin to avoid tumbling erratically. Nobody cares which point on a baseball hits the bat, although they do care about spin because it contributes to path changes via aerodynamic effects.