No there is no use for the gold coat, its just marketing crap. It does not help corrosion (copper does not corrode), and it will actually boost galvanic corrosion if you happen to have a aluminium tank or radiator for example.
Gold does not transfer heat that great, silver is actually better. But anyway, since its just a very very very thin layer, it wont do any diffrence in performance. And it if it does make a diffrence in performance, its for the worse.
