After a scare when removing my TA dust caps for the first time, not knowing if the threads or allen key hex was going to let go first, I decided as dust caps they were questionable. They never went back on.
As a mechanic I found them equally useless, and periodically time consuming to remove. Others can use them, but I will not use them on my bikes. I never bothered to remember if the Patent or Brev. Campagnolo caps were the sought after parts. Regarding tire valve caps, when riding with a group and the group is kind enough to wait for you to exchange a tire, removing and replacing valve caps is just not polite to their time. I ditched those long ago too.
I do like the chrome versions of crank fixing bolts though, but that is just the SoCal Junior category racer still left in me 35 years later.
John Jorgensen
Torrance CA USA