Funny you mentioned that. I was riding to work one morning while still dark and the low beam suddenly failed. It took a few moments for my old brain to register what happened. While I was still visible to other traffic the position bulb offered no assistance in night time navigation. A few days later I replaced the position bulb with an LED of considerably greater luminescence. I don't know that it would be any better in a sudden failure but I am more visible to others.... not a bad thing!It's also a "backup", if the LOW beam fails you're still kinda visible, hence it's always powered...
(like the H7 failed on my GF's NT in Norway, but I still could locate her in the traffic behind me...)