Sorry if I am off base on this one, but not being able to cash out via PayPal would make me just want to use TipJoy instead. Even if I do ultimately donate my money to charity, I'd still like to have the option. The FAQ indicates that you can put money in via PayPal, but it appears the only cash out option is an Amazon Gift Card?
Still, good work on coming up with some sort of money maker for Twitter. They can't seem to do it :-).