Predation is what makes evolution creative: without it there would be no arms races, no great feats of evolution, and a far less beautiful world.

In some ways, maybe it does do good. I don’t want to make an argument for nuclear arms, but predation as a mechanism forces organisms to adapt, to change, to be better, to escape, or to kill. If you need to eat, then you’ve got to eat. A cheetah is not going to run at that speed unless it has to because the zebra is capable of escaping. So it leads to much greater feats of evolution would ever have been possible without it, and in the end, to a much more beautiful world.