Nah, the batteries are easily replaceable and cheap in bulk. They are surprisingly easy to see in flashing mode. I wouldn't really bother with the steady as it'll get lost in the sea of lights.
I'm the only person usually gun running in the middle of the night in R.H. Cars act like they've never seen a flashing headlight on a bicycle around here.
The easy take on/off ability is a super plus.
Why does this bike look so familiar:
http://toronto.craigslist.org/bik/192676830.html