Tell HN: A Facebook Charity to gather all free credits?

Facebook seems to be handing out free credits to everyone (10-20 credits). Acording to Facebook 10 credits are equal to 1$. Even if Facebook pays just 40% amount to the app developer, given number of Facebook users the amount is quite significant.

E.g. Assuming 20 million FB users (who aren't interested in playing games or using credits) get 10 free credits on average and donate them to the charity app (by just clicking a button). The final amount would be ~ 20 mil * 1$ * 40% * 20%( participation) = 1.6 million dollars!

What do you think about this idea!