Back in October of last year, the European PSN allowed users to fund their wallets using money they have in their Paypal accounts. It appears as if the option has now been added for North American users as well.
As you may have already known, the recent PSN maintenance would have added this feature among other things as well. Nobody really knows why the maintenance took longer than expected, but at least the PSN is now back.
So the next time you log onto the PSN and don’t want to add funds using your credit card, you can use the Paypal option instead.