This relates to the difference between those European countries and the U.S. in terms of how driving is treated. To put in simply, in Western Europe, a license to drive is expensive and difficult to obtain and easy to lose. In the U.S., a license is trivial to obtain and very difficult to lose. Think of how many times people are struck by motorists in the U.S. and the motorist says, "I didn't see him." and gets off without even a citation. In Europe, that's an admission of guilt and incompetence to drive.

Therefore, their motorists tend to be more highly skilled and more attentive to what they are doing. Thus, their cyclists are required to use a light that allows the motorist to accurately asses a cyclist's position, which a steady light does. Here in the States, if a motorist can accurately assess a cyclist's position, then he/she is more likely to cut it too close and it is only a matter of time until one of our incompetent motorists misjudges the size/position of his/her car and ends a life. We need a larger buffer of space here, so we use flashing rear lights on bikes because it is more difficult to precisely locate where the light is and that usually causes a motorist to give more space when passing.

To avoid target fixation problems, use a light that is too bright for a motorist to stare at and aim it where their eyes will be. In my opinion, wimpy lights like the Planet Bike Super Flash and Super Flash Turbo are just bright enough to attract drunks. Dinottes, and similar extremely bright lights, do the job. Of course, this job would be better done by removing the ability of drunks to drive, but that's more of a P&R topic.