If every single person who wanted to help out looked for the most efficient thing to do on the margin, then there would hardly be any malaria patients. The most efficient opportunities for philanthropy would be exhausted. Then the next most efficient, then the next, and so forth. Maybe eventually we'd get around to giving these kids morale boosts, but if we didn't, it'd be because there were more important things to do.
If every single person who wanted to help out looked for the most efficient thing to do on the margin, then there would hardly be any malaria patients. The most efficient opportunities for philanthropy would be exhausted. Then the next most efficient, then the next, and so forth. Maybe eventually we'd get around to giving these kids morale boosts, but if we didn't, it'd be because there were more important things to do.