Maybe paypal is thinking that with bticoin they are going to act as an escrow so to speak. Buyer pays Paypal, buyer receives product, buyer confirms product is in working order, Paypal releases funds to seller. This would be the first large scale escrow company and Paypal would be justifying their existance and their right to skim a couple percent off the purchase. Without Paypal doing the escrow, it would leave them vulnerable to customers simply skipping them completely as they have no value to add. For Paypal to succeed with bitcoin they need to make it the first and biggest way to pay with bitcoin on ebay before any other company accomplishes that task. Once it is the new norm, people will use paypal only for bitcoin transactions and nothing else.