Don't knock it. I live in a community where it is suicidal not to be lit up like the 4th of July. I have 4 lights on the front and two on the rear. 2 on front are Cateyes and one of the rears is the Planet Bike SB. I have been left turned, cut off and backed out of driveways on numerous times. I have heard all kinds of excuses like you don't belong riding here and I didn't see you, you don't have the right of way, so I will cut you off and kill your bicycle riding ass.
Hickydog, you do what makes you comfortable. The batteries are just a small part of the cost of staying alive and in one piece!