Good points... True there are no repeaters on the circuits, but they do have something very similar called a doubler. Same beast that does the same thing, just works differently.
What they are referring to as "high voltage" means that there is "span" power on it. Off the top of my head I'm going to say about 130VDC. Pretty hot and will knock you on your butt. Distance from the CO for these is not really an issue because of the doublers. I've seen circuits that had 5 or 6 doublers on them.
As far as the cost, I don't think there is a price difference on the circuits. IMHO, it's just a matter of preference or availability of pairs or equipment for the carrier.
