If we think at the universe level, we are not killing machines!
YYY is killed. With an extremely high CPA.
Evaluate: We sleep 8 hours, function twice as long, sometimes even three. Who else can boast like that?
Zzz: Giraffes sleep about 2 hours a day
kkk: Giraffes conquering other universes, ruthlessly destroying all intelligent races leaving behind only ashes :)