Right, that's the laws' practical value. I'm questioning their intellectual merit since these laws look incoherent. And there's a practical downside, too, which is that by legalizing war, we normalize it. Of course, war was normal before there were any laws of war since we're naturally warlike. But one way to develop the sensibility needed to be disgusted by war (besides participating in one) is to notice how absurd the laws of war seem, given war's inherent barbarism (and thus its position outside the proper realm of law).