If you as a motorbike rider (or as a car driver, for that sake) keep your headlights on, you are at least seen and noticed. I agree that a very bright, dazzling light can make it difficult to judge distance, but the point is that I will be aware of the rider - in dawn, dusk, rain, fog, even bright sunlight etc. Just look at an oncoming car - which one will draw your attention first, the one with lights on or the one without? So here here all motorized vehicles are obliged to have their lights lit, 24/7. Works well, no increase in accidents after that law change was introduced. I do remember the discussion when it was to be introduced, smaller vehicles would "drown in an ocean of light" etc. The experience showed the contrary, surrounding traffic was more easily seen, on two or four wheels. Bright colours on bike and clothing is good, but a lit headlamp is much better for getting noticed. And light use can be regulated by law, vehicle and clothing colours hardly so.