Marvel’s regular cover stock, the same as the paper used for its interior pages, is widely reviled by comic retailers. While some other comic publishers use self-cover formats (the same paper on the covers as on the interior pages), Marvel’s paper stock is generally thought to be the worst of the lot as far as showing damage.
So the heavier cover stock is going to be widely supported by the trade, although the metallic ink is going to bear the taint of early 90s enhanced cover excesses for some. That era, which saw numerous special cover treatments used to drive collectability, ended in the collapse of the speculator market that was then driving sales. There’s no sign of that happening now, but metallic covers on an event book will create uneasiness about a potential pending apocalypse in some quarters.