Thanks for coming back :)
Here's an example to explain minimum payout, let's say you set the minimum payout to 20$. Then you will only downvote posts that have a payout that's higher than 20$. This is done so that you don't downvote "small abuse" or "small bidboting" where you downvote a guy with 50 cents payout. I think it's better to go for the people who are earning a lot by abusing and then go for the lower ones.
Edit : upvoting to un-hide myself
Thank you @howo. That's very helpful.