I can't imagine a purpose for one, but that doesn't mean someone won't find it.
I scoffed at why someone would ever want a camera on their phone and now I'm like a Japanese tour group with my cell phone.
IIRC, there were some "police type" shotguns that had a DA(ish) trigger pull so the fuzzies didn't get confused and light off their shotgun prematurely
still makes them. I think it's silly and unnecessary, but someone is buying them.
"Our contract called for 16 cases of rifles and ammunition for $10,000 dollars, not a machine gun...........That is our present to the General"-Pike Bishop
“When fascism comes to America, it will be wrapped in the flag and carrying a cross.”