I have used foil on my rotary cutter and it seems to have worked. I haven't tried it for scissors.

It seems to work for me for both scissors and pinking shears. But then my scissors are not expensive at all. The expensive one would be worth taking to be sharpened.

Doesn't only work with scissors will help to keep an edge on your rotary cutter, won't take out nicks but definitely cleans and sharpens them.

I'm on the side of "it works". I make my own refilled Keurig cups and I cut tinfoil strips into fourths to place over the tops. To cut the tinfoil I used an old pair of scissors that I normally used for crafting. Suddenly became aware how sharp they had become when I accidentally picked them up to cut some fabric and found they cut really well whereas before they wouldn't cut fabric at all

I've never heard of that but do buy the cheap sand paper from the Dollar store and cut several slats in it and my scissors are sharp, works every time.