Dummy discs are really dumb but I don't think a billet caliper cover that keeps it clean/purdy looking is any different from all the other billet covers/stick-ons that folks install under the hood or inside the cab for some kind of blingy/purdiness.
a billet caliper cover isn't keeping anything clean. So your caliper hidden underneath stays clean, but the cover gets dirty. That excuse is a lame attempt at justifying the rice aspect of it
As for making it look "bling", powdercoating or painting stock calipers, thats making them look "bling". Adding a stick on fake big caliper cover, thats as cheesy as it gets!
Replacement knobs/buttons for the interior that are billet aren't nearly as cheesy, they're simply accentuating otherwise boring parts. Same for under the hood. A better analogy would be adding a nitrous button on the dash thats not hooked up to anything, or adding supercharged badges to the outside of the truck on a model year thats not supercharged.
Bling on a non-functional item (rad caps, buttons), okay
Bling on a functional item (painted calipers, polished blower), okay
Bling on a fake item made to pretend to look like a functional item (stick on big calipers, s/c emblems on n/a trucks), LAME