You are full of crap. Its been proven on a dyno that royal purple DOES free up an extra 5ish horsepower in a honda. Its thinner, its slippery, it costs more.
Long term? I dunno. Protection, no idea either, but it does do something that mobile 1 does not.
P.S. If any engine is opperating in the "very fucking hot" range, there is something wrong with it. Fix it.