Possibly a bit more rpm and a bit more speed in the air at a given rpm. If the 3- blade is working for you, why change?, although it's fun to experiment and see what else works. The recommendation follows the accepted theory of change in pitch and/or diameter when going from 2 to 3 blades or vice-versa.
If you stay at the same diameter and go from 3 to 2 blades, you decrease the total blade area, which decreases both total thrust and induced drag of the prop, Increasing pitch will somewhat compensate for the decreased swept area of "losing a blade" and induced drag will be a bit less, so efficiency is greater, and the increased pitch also takes larger "bites" of air per revolution, increasing forward motion per revolution. These are all theoretical norms, which vary due to prop blade shape, available torque and actual prop disc diameter.