It's about removing unearned rewards and persuading people to be less selfish in their actions. We can point you to dozens of accounts who just buy votes or self-vote with practically zero community interaction. They are milking the reward pool. We also act in cases of plagiarism or impersonation.

SFR hands out their tribe tokens to contributors and you can use them to buy votes. I use mine to buy votes for others who deserve more. I can find plenty of great posts that make cents whilst those with the right friends can make dollars for a selfie :)