Originally Posted by rm -rf

Even the very narrow beam of the 2W on the left is effective out on the road, it widens with distance, of course.
The narrow beam allows it to send more of it's light way down the road, but still wide enough at a moderate distance to cover all lanes.
The 150 is a lot wider, for coverage on curved roads and nearby drivers in another lane.
I aim the 150 light slightly downward. That way, part of the main beam is still above eye level, and the bottom of this wide beam lights up the road behind me.