Inexpensive lights may not focus their beams well, so light goes where it isn’t needed or wanted. German lights use a different beam pattern, flat across the top so they don’t blind oncoming traffic. They also concentrate the light on the road, where you want it. If you are able to mount your light in a lower location than your handlebars, that helps too (mine are on my front racks).

The Busch & Müller Ixon lights do have high and low beams. The main advantage to using the low beams is the charge lasts longer.

Busch&Muller battery powered bicycle lights