Combination tools alway come at a cost of function. One tool designed to do one job is the best.

It's like that with flaperons. When you apply the flapperons, you loose some effeciency in the aileron area, and along with the flaps deployed, a little to much aileron stick will result in a pile of parts. What happens is with flaps, you are flying near stall speed, When you kick in a bit of aileron, you are deploying more flap on one side and less on the other. Tip stall soon to follow.

There are only a few planes I've seen that could benifit from flaps, and all were heavy pattern planes, war birds, or jets. Nothing in the trainer to third or fourth plane needs flaps. Also a newer pilot usually isn't ready for that complexity yet.

Don