Arnold yes, as a biker I'm happy to have my car lights on (and do). The whole point of bikes having lights on them is so you can see them, spot them against the background. For example you will spot a light out of the corner of your eye so you probably won't pull out on it, whether it be car or bike. I don't mind bikes blending in against cars, you wouldn't pull out on either. What I'm worried about is vehicles blending in against a background, especially if it's sunny or overcast, the stupidly two extremes we get a lot here.
People say "if you can't spot a car then you shouldn't be driving" but how many times have you been driving down a suburban street and gone to execute a manovure around a parked car only to find that car a little bit further down the road was tanking it and is heading right for you? With his lights forced to be on you would have judged his approach speed much easier.
Or on a motorway when it's slightly overcast, someone in a grey/silver car is sat in your blindspot, well you think they are but the rain on your side and rear quarter windows is blocking your view. Are they still there? did they drop back? have they gone to undetake you instead?
Just about to cross a street, can't hear anything because the ambient noise is high (thinking city centres), you go to cross but that car that was double parked has just decided to set off without looking, with DRL's if his engine was on you'd have caught the lights and perhaps looked a little further into the car to see a driver in the drivers seat.