So, no-one has touched on these two aspects of "shiny" props
a) they are terrible in the sunlight especially if you polish the back side, Catch the Sun just right and get blinded by the reflection and you have it on the entire disk as the prop is turning, this is why most props are painted black on the back side.
b) it's been proven time and time again that the smoother the props finish, the slower it is. I can't remember who did it, but someone took the same prop and ran a polished version vs a painted version at Reno and the painted version was 1-2kts faster. Perhaps that's in the variability allowance, but then there is point a) above
My .02 on the topic.