You don't need to be that strong to hold up a dictionary with your arms. Now try doing the same thing but attach the dictionary to the middle of a 3 foot piece of rope holding the rope only by the ends. It is not nearly so easy. This is one of the principals of force that can be demonstrated by using simply a piece of rope. By the way the answer to the "tug of war" question is it would be a tie ("For every force there is an equal and opposite reaction". Rope comes in a 50 foot coil.
Products being sold are not toys. They are for Educational / Laboratory use only. They are not for use by children 12 and under.