The aim of lubing the chain is to get the lubrication on and inside the rollers - not the side plates. Yes - they will go rusty in certain conditions, but wiping them with an oliy rag should suffice
I doesnt but if the chain is not lubed and the rollers ( for want of a better word) are dragging the X or O rings that are actually very thin or fine get dragged out of position and then the chain is fecked