I guess I don't need to worry about it in that way. But I do need to worry about it in terms of pursuing a wounded lord who chances on battles along the way. Same for responding to a siege -- there are usually battles following these.Does it matter?
If you fight them, the odds of the AI engaging in follow-up fights with the player is basically zero. Probably 97% of the time they get beaten and captured, so their health percentage is irrelevant. In the rare case they win, the AI takes the player captive and their status doesn't matter. AI-led armies rarely chain battles together. They essentially never do so while the player is serving in them (autocalc allows the occasional escape, but in missions two armies fight to destruction) so you're hard-pressed to see if any individual lord is on the field or not. Finally, whether they are up or not isn't particularly noticeable or decisive for any reason. The bonuses they grant are haphazard at best (party leaders don't lead formations unless in an army + random perk selection + random selection of formation to lead) and even if the stars aligned to get a great infantry captain actually leading the infantry formation, odds are they will go down in the first two minutes due to being mounted.
It is the sort of thing you'd only notice if you were in cheat mode and stalking a certain lord via the dev console.
I can provide a lot of reasons why this perk is unbalancing garbage to the gameplay. The only reason I hear to go ahead and heap the garbage on the gameplay is that some people have whined about their risky playing behaviour that they haven't practiced their playing skills to match is resulting in them being wounded, and not able to fight until healing to 20%. A simple fix for this is to hire a skilled companion to play medic.
What a horrible game-design philosophy, to even take up the space of a perk with basic nerf garbage like this to accommodate those who don't want to learn to play.