In Germany it is
verboten to activate your high beams withing city limits, and it is
verboten to activate your high beams in the presence of other vehicles in front of yours, whether oncoming or traveling in the same direction.
My opinion on the matter, however, is that regardless of the law there are much better alternatives to high beams in order to increase the probabilities of making it from A to your desired B. The best of them is to assume that I am invisible. Under no circumstance I take it for granted that, for example, somebody looking in my direction actually saw me and is going to react in any predictable way, or that somebody is going to glance at the mirrors long enough before changing lanes, or actually care that a bike is there.
Since I adopted this mindset a few years ago I got my self into trouble once: at 10 mph at a junction when I took a chance overtaking a delivery van and the car in front of it didn't see me coming and veered left to avoid a bicycle on his right -> my fault.
There are too many other interesting activities to do while driving (texting, checking make up, picking nose, smoking...) and no extra light will increase the awareness or improve anybody's attitude, focus and commitment to what they are doing (driving)