I agree. It's a pity in some ways that we teach Vx and Vy as "best angle of climb" and "best rate of climb". If a student is told it's the best then that's what he feels he should use.
There's no reason at all to use Vx unless you want the best possible climb angle to get over an obstruction. Vy is usually also not necessary in the early stages of the climb. A friend of mine had a sudden EFATO while still low and nose-high. The effect of this is that the aircraft immediately loses speed, and hence control authority, and will not regain it until the nose is down and speed has picked up again. Just rotating the aircraft to get the nose down requires energy which has to be regained. He was not able to make a controlled landing and fortunately was not badly injured in the resulting crash. On the other hand, if the failure had occurred at a lower altitude, but with more airspeed and a less nose-high attitude he would have had sight of the ground ahead and stood a better chance.
Mechta has it spot on, if the donk fails you are in a glider, but one with a far worse glide angle than the 28:1 of a basic 2 seat glider. Hanging it off the prop at low altitude is not a good idea. An immediate pull back to maintain Vx or Vy is just as bad as the glider pilot pulling hard immediately after launch.