rivets why?

Why are rivets used to fasten gable rakes, sidewall flashing, and ridge caps? Would not self tapping screws be easier?

Stainless steel ring shank air nails would be really easy.

(I guess people aren't ready to have a riveting discussion about this.)

Rivets stay where they are put.

Screws will move.

This is the type of discussion that could get seriously technical and over my head in a hurry. I guess the consideration would be shear vs. pullout with a little aesthetics thrown in. Rivets are neat and clean looking. They'd have more clamping strength than a screw if the screw was only bearing down on a neoprene gasket without splitting the gasket. Rivets wouldn't "walk" out per se, but I know that shear forces work on them and over time they can get deformed and lose their clamping strength. There's not a whole lot of flange on a rivet. Would also depend on the rivet. Then again, when I'm looking out over an airplane wing in a jet liner, I can't recall ever seeing the pieces fastened together with screws. Then again again rivets don't normally attach anything to a substrate. I have sometimes attached flat sheet to a substrate and then riveted to that.

I agree egg, size does matter and I've found many loose over the years. But were they inadequately set or simply too small?

Seems like the common spec is for a household/ downspout 1/8" rivet. Yet a much heavier steel ridge/ hip cap up there in the wind and sun seemingly has more stresses, shearing going on than the common downspout.