I could see such a bolt and its technology being used as a fastener for a tension pulley with all the advancements in heat treating and fusion of other strong metals.
In this case, it's lateral pressure. I guess a tension pulley is only keeping minimal lateral pressure on the belt to keep it within operating tolerances.
My March pulleys are aluminum, and yet just a tad heavier than the factory steel ones because of the aluminum thickness to sustain such stresses.