short sight radius
We finally have CCW in Wisconsin.
Since the law changed in November, lots of guys at our local club have some to matches using concealment holsters and smaller guns. Their intent is to practice with what they carry with, and I think that's an excellent idea.
They are finding that smaller guns have shorter sight radius, and if the grip is short, the gun feels different in the hand. They're finding they have to downshift a few gears to get good hits on target, in comparison with the speed they could achieve with competition holsters and specialized competition guns.
I've always competed (mostly) with whatever my duty gun was at the time.
You can only learn from experience if you pay attention!