There will probably be a dozen reasons posted why the killshooter should remain on, but I'd be ok if it were off.
I'm not that great of a shot and have killed myself a few times trying to clear a friendly's six, especially if the friendly is in a bomber.
OTOH, I suppose it is good in the sense that at least some of the people chasing me must have killshot themselves at one point or another trying to hit me.
shrug.