Triggers don't have wires (except on some crew-served guns, anyway), but triggers do have a direct connection to the firing pin, because they are a critical component and there must be the minimum possible chance of malfunction. Actually, ALL components of a gun are critical, and they all need to be as reliable as possible, including the light. So yes, it is a valid comparison. (there's a reason the expression "shooting in the dark" exists, and it's not a good reason.) Guns exist to kill things; all other purposes, including target shooting, are secondary, because guns were not invented to help dispose of tin cans and china plates. With that kind of capability in your hands, every single part must work right at all times. Neither you nor your target will appreciate it if you panic in a dangerous situation, because you need the light to turn on and it won't because the wireless switch stopped working.
I'm an IT guy, trust me: wireless will never ever ever be as reliable as hardwired.
A Fenix won't last long under the recoil from a shotgun anyway. A gun light needs to have springs at both battery terminals, to protect the circuitry against shock from the battery impacting the driver board.