"Seriously, has anyone here used lights while flying professionally,during daylight hours, for collision avoidance?"
Mixture
For collision with what ?? We use lights for collision purposes all the time!
Flying in any low visibility high intensity lights are a must!
Coming out of cloud on minimum RVR high intensity lights are a must have!
Every time I get a clearance to enter and line up on go the strobes!
Lights in poor visibility not just night are a way of alerting the pilot to a Hazard in all the gloom even buildings or structures which are in our airspace!
Hence why the authorities regulate for their use!
When you are struggling to see in the gloom especially with the thin arm of a Crane painted grey blending into the gloomy grey background intensity lighting will leap out and warn you!
Sadly this poor pilot saw nothing until the bang and the seconds he had to realize that as the ground hurtled up at him.
Whether PB had a mechanical problem or made a tiny error he paid a high price which could have been avoided had that arm been fitted with intensity lighting.