The yellow airplanes in the museum hangar are all trainers, and all are tail wheel equipped. When pilots taxi too fast and have to brake quickly there is an excellent chance the aircraft nose will contact the ground or tarmac. The outer part of the blades shatters and the ground crew has to install a new prop.
However, the Harvard has a metal prop. If you put a Harvard on its nose that means a new engine because the prop is metal. The destructive strike forces go into the engine and not into the wood.
If a metal prop strikes the ground the energy of the strike bends the blades and instantly stops and destroys the engine. Wood props are cheap to replace compared to the cost of an engine.
In the photo room at the entrance to the hangar you will find plenty of photos of prop strike accidents.
Most training schools in BCATP had many wood prop accidents. The rule was that if you were the technician who replaced the prop you could keep the broken wood prop. Many were beautifully trimmed and refinished with a clock or barometer installed in the hub.