As GigaOM writes (linking to Steve Job’s statement on Apple’s web site):
Now there’s a way to annoy the people who have stuck by the company through thick and thin. Today, realizing that Apple’s goodwill was at risk, Jobs announced a $100 credit to all early iPhone buyers, promising to do the right thing.
I see this as another marketing trick targeted specifically at Apple fans. They WOULD use this credit one way or another. As a different example, myself – the iPhone is the first product by Apple I have purchased in my entire life (and not even for myself), such credit is absolutely and perfectly useless.
Good thing I bought mine less then a week ago.