I'm not an expert in these metals

All I can say is that palladium likely has a lot wider use in industry (for example, car making) than the other precious metals. This metal is known for its extremely high absorption capacity of hydrogen. This property allows to use the metal as a medium for efficient and safe hydrogen storage. Indeed, it may be not as efficient as liquid hydrogen itself, but I don't think many people would want to drive a car which can easily turn into a sort of "hydrogen" bomb, especially when someone actually gets blown up