It feels like being taken advantage of. It's taking the worst part of crowdsourcing, which is that the majority of the gains are concentrated in a few people while many people contribute to success, but receive a pittance, and making it even worse.
I'm not convinced that the raw economic incentives work out, either. I have tons of opportunities to help people. Supply of people who need help greatly exceeds my ability to provide it. I can't imagine paying for the privilege.