Other things you learned with an erector set:

Screwdrivers can slip and puncture your hand. 

The electric motor I had was 110V so it plugged into the wall.  It had a transmission that allowed you to make things run both directions.  If you got your fingers in the gears you go a blood blister.

The education one got from using an erector set carried over in life.  One learned not to stick you hands in moving gears and not to put your hands in positions where tools could hurt them.