I agree, anything goes if needed for off road riding. I believe though this is a discussion about lighting for road/street/urban riding.

Another poster mentioned reading street signs. If too close or the sign is off to the side I cannot do that with car low beams, or on occasion even with high beams, either. It would help if more street signs were reflective. If done properly they are readable with a lot less light than usual. If I know I will need to read unlit signs I carry a fairly powerful LED flashlight in a jersey pocket. Sometimes actually easier with a bike as the headlight is easier to aim at the sign than a car headlight.

Plenty of misaimed car lights around too. European car lights are required to have a much sharper cutoff than American ones. So far s I know American car beam shape standards are pretty much unchanged since the days of 35 watt 6 volt incandescent car lighting. Those were glow worms compared to most current car lights.