What should a paid product ranking actually prove?

I’ve been thinking a lot about this while building RankArena. Most paid leaderboards tell you what someone paid and where they rank, but after that, there’s not much to judge.

With RankArena I’m trying to make the position itself measurable, impressions, product views, outbound clicks, rank history, time at #1, outbids, comebacks, and so on.

So if someone pays for #3, they can eventually look back and see exactly what #3 delivered. I’m curious where people draw the line here.

If you paid for a ranked position, what would you actually want to know afterward to decide whether it was worth it?