I mean, if I had to say the problem with "yes-kill" policies is that if you get used to killing it can become the "easy" problem solving solution to maybe some instances where it isn't appropriate or you've just become impatient, with giving yourself the ability to judge whether someone should live or die your emotions, opinions, etc can get in the way- not to say that the court or some fuck-ass judge is any better, but you should get what I mean.
The other problem is that your enemies won't be as willing to negotiate or cooperate with you because you'll be the guy who kills people and you'll always be known as a murderer/killer. Not all of them mind you, but some of them: they'll be less inclined to come quietly, they'll make stupider mistakes, they might even take bigger risks, etc.. It'll complicate any relationship you have with villains even if you have a personal code or process, they'll still resent it, obviously.
On the "pros" side of this argument though: if you're a caped-crusader you're already judging others and you're already putting the law into your own hands- the true nature of being a hero is sticking your nose where it doesn't belong and NOT minding you're own fucking business, being an agent of change in a world without justice..... So why the fuck not? If only for the "straight and cut" scenarios.
Like this anon stated: >>95460174 >"The life of a little girl isn't comparable to the life of her killer. It's not even close."