Yeah I find the whole subject perplexing, I'm reading that after wrapping, head temperatures are lowered, which doesn't make any sense to me, and a couple other claims which strike me as contrary to what I would imagine. I mean, if it were that easy to send the heat through the tail end, why does the bike come out year after without any changes I might wonder.
I can only make a comparison with a certain water heater that I work on which is somewhat unique; [not that anything is these days] it's a high efficiency down directed burner; the burner / heat exchanger reduces to a 180 degree elbow and rises to a perimeter coil spiraling downward toward a condensate trap / elbow directed vertically upward and toward a vent termination.
IMHO, the water vapor produced, condenses, in the incoming cold lower portion of the heat exchanger, then flashes [speed of sound when finally re evaporates] as it rises and drops slightly in absolute pressure.
In any event, everyone hate's this water heater [model] because it's so noisy [except when you're there]
Where was I going...
if the pipes are wrapped, there's less heat transfer so the interior surface of the pipe is higher than design; the metal temperature operates at a higher temperature; perhaps the full run of the exhaust acts as HC burner; no cat required, terminal temperature would be higher, but I don't see how this could translate into cooler head temperature.