Do you believe that Balsa and ply is somehow inherently weaker?

If so you are mistaken.

Foamies get dings and scratches that are difficult to remove. Typically beginner's foamies look pretty bad after a very short period of time.

While you can repair clean foam breaks with plain old white glue, more often than not the types of crashes beginners experience are beyond repair.

With Balsa & ply planes you can walk into any hobby store, pick up some hardwood, balsa and covering and restore your damaged plane to better than new condition with a bit of work.... particularly the more simply built Trainers & Stiks.

Don't discount Balsa and Ply, because of the vendor's often repeated ( but erroneous ) "foam is easier to repair" mantra... That is merely a sales ploy.