And even if we assume that there is no further improvement in perceived smoothness or your ability to predict motion; a monitor that updates every millisecond i

And even if we assume that there is no further improvement in perceived smoothness or your ability to predict motion; a monitor that updates every millisecond instead of every four millisecond will show you any new information earlier, like say somebody appearing around the corner. It's basically a 1-2% boost to your reaction time just because you get to react earlier. At a competitive level that's nothing to sneeze at