I understand your thought that flashing headlights will get drivers' attention. I suggest it works that way too good. Flashing white headlights demand drivers' attention, selfishly taking it away from everything else in their field of view. That makes a distracted driver, which is unsafe for everyone else on the road at the time, including cyclists who happen to be in the lane with them then.

Flashing white lights, especially very bright white lights like the Magicshine, should be reserved for emergency vehicles only. That's obviously my opinion.