> Allow me to sidle into another quadrant of this topic
> and pose the question: What is the PURPOSE of these
> trim pieces? Simply to dress-up the rain gutters? To
> protect the rather delicate metal edge?

more likely to keep the humans from getting cut on the sharp
metal edges ...quicker and easier to pop a plastic trim piece on
the edges than to spend time grinding them down to a rounded
edge. that would be my guess.