The announcement (by ebay) suggests that the move will help improve confidence as well as further reducing the limited amounts of fraud which occur on some types of transaction. Sellers with low feedback, or who list specific items, such as computer software are already required to accept payment via PayPal.
Under the new eBay policy, sellers will however still be able to accept payments via other services, provided they are on Ebay's approved list. Goggle Checkout (a competitor to PayPal in respect of retail payment services) is notable by it's absence from this list of approvals.
Source: Wikinews
*Making eBay Safer and Easier with PayPal - Ebay General Announcments - March 2008". eBay Inc., 24 March, 2006
* "Accepted Payments Policy". eBay Inc.,