Most cars use the low beams for DRL’s some have an independant light all together (reference Tahoes and suburbans) Some use a small insert bulb in the headlight housing just for the reflected light and not actually a beam ( some Acura’s and BMW).
DRL’s on bikes are mandatory but highbeams are preached for daytime use. Everyone form instructor, Department of Motor Vehicles and even local law dawgs will tell you to use them. The logic is that of the same that NHSB used to push DRL’s on modern day auto’s. That yellow jacket , cool or not, is not gonna make you visible in a low hanging sun… or when oncoming traffic is adjusting from shade to sun or vice versa. If it bothers drivers while you are behind them, they have options…. learn and use the flip pedal on the bottom of the mirror to redirect the glare, or change lanes. Your safety is your responsibility and concern and should be foremost so …not the drivers ahead comfort level.