Facebook as payment system? I still don't have enough confidence on how secure their system is. Also, sharing home address with them is not a smart move.
It sounds like they should let you update your privacy settings to automatically reject gifts if you dont want to share your address... Something like "sorry, this person is not accepting Facebook Gifts".
And why would they not try to tease you letting you know someone has sent you a gift? I wonder if at some point they'll have a malfunction that tells everyone a gift is waiting for them, and so they need to fill in their address details..
I know it's not the same thing that the OP said, but, given Facebook's track record with privacy, there is no way I am giving them my CC number and home address.