OK disagree, that's your prerogative, but you haven't given readers any decent analysis. In fact you make a pretty dangerous claim that "you don;t need anything like as sexy on a rear light as a front."
Why would one not want to be especially visible to traffic approaching from the rear? Certainly I would want to be -- and am -- lit up like a Christmas tree. That's why I run three rear lights -- two high-quality (battery) lights on seat stays, one on rack bracket, fly a reflective triangle and wear reflective clothing.
Yes, cheap battery lighting is ubiquitous, but a lot of it shouldn't be allowed on the road, IMO. There are certainly good battery headlights available (and I review some on my lighting page referred to above) but if you consider the overall cost (incl spare/replacement batteries) there is not ultimately not much difference in overall cost. Again, I say, dynamo systems are just the thing for busy commuters. No hassle with batteries, reliable and ultimate cost/benefit.
Have you actually tried and compared different systems?
just my opinion, the simple words, no more no less
because every accident I've ever had happened from the front when people in front of me did;t see me coming, that's cars, scooters and bikes
I use rechargeable batteries for rear lights anyway