I'd have to agree with you on many of your points. Convenience is one reason to buy a kit
I usually go that way only if they're unique. I bought a grille assembly kit and have clutch head bolts for my rear fenders coming, which aren't generally available at any local hardware, or my go-to online source for hardware, McMaster-Carr.
I find it interesting that you found fine thread captured nuts or threaded holes. There don't seem to be many of those at all on my AD. If you're talking about clip nuts, many of those such as the lower grille apron are for sheet metal screws.
