There isn't much to see - I ride mostly desolate back roads on my commute. Im more concerned with having puncture resistant tires than seeing what is around me. Looking around would let me see oh, well... trees, farm fields and maybe some road kill.
I can see where a helmet light would be useful if, say, I were rushed by a dog from the side... but that has never panned out.
I admit that I was concerned with this when I first commuted after dark, but dogs seems to change at night.
They appear to lack their normal daytime willingness to give chase.
Occasionally, a deer will be startled by my presence, too, but they don't do more than stand there or scamper off.

I find that once out in the inky black of the back-road night, almost any light will illuminate these things. I am looking around at a brighter bar light to replace the current one and am liking the BikeRay's. When I get my dedicated commuter bike completed, I will likely get one.

I do have a short city section of my ride, but there are street lights and other illumination along that section. I am content with the bar mounted light as my main source of illumination. As I said previously, I DO like the helmet light as a means to signal motorists, and they are useful for "looking around." But I ride the same road going and coming. I've already seen what is there to see, on my way in.