_design features which are included because we value them (apparently) but they serve little or no purpose_

well.. sure. I mean, once you have Helvetica and Times, all the other roman fonts are basically wasting my time.

I would argue the rivets still serve a purpose. Maybe its how I wear them, but I have torn the pockets off jeans.

The Iconography of Instagram and the resurgence of Polaroid style cameras..

The iconography of the floppy disk as 'save to disk' icon probably won't last much longer mind you.