Depends on the situation. Unfortunately it's a
necessary story concession to
gameplay and the limitations of the game engine, where an enemy is defeated gameplay wise (HP reduced to zero or near enough), and yet some are story/lore wise specifically
killed, where as others are just beaten down but are still alive, and the battle system depicts both in the same way.
And the flipside of that, is much later in the game, there are a number of situations where it is turned around on the
player, where due to an enemy plot coupon
they are beaten down to within an ilm of their life, despite you managing to 'defeat' the enemy anyway (I don't think you're up to that part yet so I won't spoil anything more).
It's an unfortunate requirement of this being an RPG where battles are still fundamentally about numbers representing states of characters and how they attack and their resulting condition, and are depicted gameplay wise in the same way regardless of the story outcome (just like in old style FF games like FFVII where the enemy
disappeared upon defeat, even those who weren't actually killed). Battles are
actual gameplay, not interactive cutscenes.