I see this train of thought everywhere on this forum, but having had numerous red dots on guns for years, I've learned that irons are insurance, (dot flicker, dot completely dying, dot breaking, dot flying off the gun (MOS system) have all happened to me or buddies guns in the MIDDLE of stages). it's not a matter of if it'll happen, its when. so, why not have them there to switch over to when crap happens... yes, irons are a slight distraction, but only slightly, their pros outweigh their cons every day of the week. you don't always get to switch to your backup gun and re-run the stage.