A publisher on BMF.io should post payment proofs because it builds trust with potential users and other publishers. When people see real evidence of payouts, they're more likely to believe the platform is legit and worth their time. It boosts the reputation of both the publisher and BMF.io itself. Plus, sharing payment proofs can motivate others to stay active or join the platform. It's kind of like saying, "Hey, this actually works—I got paid!"