Watts have less to do with brightness than the optics and grade of LED. FWIW I run Busch and Muller dyno lights (they aren't cheap) and they put more light down the road with a 1 watt LED than many car head lights.

To the OP...I have not used that particular light, but for about the same amount of money you could get a Planet Bike Blaze 2watt and they show you what the beam pattern looks like.

Aaron