Artwork Page Sponsorships- A Few Questions

Hi,
Maybe I'm missing the point but I don't see the advantage of using Artwork Page Sponsorships.
My understanding of how it works-
I sponsor a page; visit a page (that's relevant to me) click on 'sponsor this page' link, post the code in my website (or elsewhere online), tell FAA the url).
So when anyone visits that page your images will feature on the third row of results. BUT "If multiple artists have posted links to the colour greeting cards for sale page, then the three featured positions will be randomly filled with images from those artists."
Q1- I'm guessing that there are hundreds (if not more) of artists sponsoring pages so the frequency that your images appear is low. Correct? But this is better then them not appearing at all there.
Q2- have people noticed an increase in sales after sponsoring any pages?
Q3- If I post the link on multiple sites or pages does this increase the amount of times my photos will feature on the third line?
Q4- I presume the code in the link that I post has to be EXACT, I can't even change the text that will appear by 1 word/add a few words

Thanks,
Patrick.