Ok, package just arrived from Amazon. You get two protectors for the $10. Guess one is for cleaning.
The microfiber cloth is super slick feeling, almost like silk. It is also about a thick as maybe 2 pieces of notebook paper, way thinner than the foam pad that comes between the keyboard and screen from the factory. Folded where you have 4 thicknesses and compared to the foam, the foam is still thicker. No way it would transfer prints to the screen that I could see.
I will try using it, it can’t hurt! I agree with barkomatic and do not think this whole thing is anything to lose sleep over. My MBP 16 is carried in a sleeve with nothing ever sitting on top of it.
OK, looks like you got the GhostBlanket, not the GhostCover posted by
@stanleystf above.
The GhostBlanket looks like it might actually help, by separating the keys from the screen. Let us know how it works out.
Of course, the absolute best separation is a physical air gap between the keys and screen. I would only use the GhostBlanket if you know or suspect there is no air gap.
The GhostCover is just a keyboard overlay, which will effectively increase the height of the keys, and unless removed every time the keyboard is used, will get just as contaminated with finger oils, lotions, etc., which will transfer to the screen, even more so because the gap is reduced. If you want to test, try coating the GhostCover with something like talc powder or oil, and see what happens to the screen.