Or just huge safety factor, depending on the possible bad conditions of use, like rubbing, sharp edges?
Likely the opposite, but still severe usage related : I had a neighbor working for the rail road company at a trial area for fret. They had ropes cut in relative short length to pull the wagons. They were twisted ropes, not overly strong but they had a special policy for them: a two times use.
Take what ever rope you may find around, use it once, put it in the trash bin, take a new one for the next wagon.
That seemed such a waste to me. Thinking of it, it looks like they had a very low safety factor to get all the elasticity available to smooth the operation. Talk about reducing the number of cycles before failure.