It will be slightly less accurate, but most of the real world accuracy will be lost in sight radius and difficulty firing a tiny gun with big hands. Years back I bought a 2" model 10 with fixed sights (square butt). I could'nt believe how accurate that thing was at 25 yards! I doubt if I could fire my newly purchased model 37 that good, but its not meant to be a target pistol. So I'd say the second part of your question is more correct.
I'm sure people that practice with snub's have the advantage of knowing their equipment and its limitations.