Those who don't have no advantage at all over those who can't.
Love that quote pax.
It's a fact.
Just yesterday I was at the indoor range doing my hip shooting (true hip shooting, belt level) and then bring the gun up to a Iso style grip and add a head shot. All under my regular cloths using my CCW holster and practice Glock 26.
Some shooters, after I was finished, commented on the shooting. I showed them my all metal Glock practice 26 (it's one of those holster molding cast aluminum guns) and my Glock 26 airsoft I converted to a laser gun. They understood then how I became proficient, but neither of them asked where to get their own.
I see that all the time. Comments like 'wow that is cool', but now 'show me how to do that'. They still just sit there and fire two handed, no drawing, at 5 to 7 yard targets, slow fire.