When discussing NPCs and death saves it's rarely about them popping back up when you don't want them to as much as them not dying when you want them to.
Outside of a few very specific spells and class features that allow you to gather not necessarily complete information from the dead, knocking somebody unconscious with a melee attack rather than killing them is one of the best ways to potentially gather information about a opposing Force.
Same for keeping NPCs and Pet focused tagalongs to cause unnecessary strife because of the math rocks not being friendly.