Let me first say this: I wouldn't have used the punching analogy. But we can talk about that another time.
This idea sounds strange to me. When I was a student of a karate school and we did nunchuku, we learned with nunchuku. I feel this kind of follows the "sports specificity" rule. If you want to be able to perform a skill, do the skill. A stick has different principles of usage than a set of nunchuku by simple construction alone. Bad advice I think.
Analogy that might fit better: This would be like telling someone that the best way to learn addition is to learn how to conjugate verbs.
"I'll use my bare hands...against any weapon!"
We are trained in wushu. We must defend the Temple!