Look at this practically. High beams during the day is a great idea for somebody running a single-light bike, because the image of a single headlight coming at someone isn't significant enough to get people's attention and let them judge your distance correctly. Even high beam doesn't help a single-light bike be seem THAT much better, but it helps some..
Our bikes' fairings are probably 2-4 times the width of the average bike, and the headlight array on the front makes a HUGE image to oncoming drivers.. The design of the fairing separates the lights significantly, making it much easier to make a judgement as to how fast they are closing.
So why care? Like the man said in Proficient Motorcycling, most drivers are NOT out to get you, so why piss any of them off by running those megawatt highbeams at them. Even in the daytime, we've got some awesome wattage up front.. even with the stock bulbs.. So I run mine went the visibility is limited by mist or very light fog, or if I'm alone going down a two-lane country road where there may not be any place to go if the oncoming car does something stupid..
YMMV.. Just my $.02 worth.