It’s not really about the amount of light (the brightness of the bulb), but the direction of the light. So I don’t really buy the argument that a single high beam is the same as two car headlights in low beam.
I use my high beam all day, but at night, I rarely use it. That’s just because there are usually cars with me in the areas that I ride at night. There’s also a lot of street lighting in town, so it doesn’t give me that much extra visibility.