PayPal's Auto Sweep is a Premier and Business Account feature that electronically transfers your PayPal balance into your bank account every night via the Automated Clearing House system. Once enabled, Auto-Sweep will continue every night until you either disable it or initiate an electronic funds transfer from your bank account into your PayPal account.
That way you do not have to manually transfer the money into bank account and it also lets you pay using credit card (if you have balance in your paypal account, it uses that as a payment method).
You can set this feature by
Login >> Profile >> My Money >> More >> Auto Sweep >> Edit