At least when you load a savegame you made during combat, you lose any progress you made since you saved. When you flee, everyone you killed is still dead, and your party's back at full strength. And, you know, I'm fine with that, as long as I can't flee with enemies breathing on my neck, standing in a pool of cursed fire, with everyone in my party about to die. It's like "Well, you know, if anyone had moved at all, they'd have died, so we just fled instead." That doesn't make sense.