The main benefits are really showing at merchants, because they dont have to pay CreditCard fees.
Don't forget about the chargebacks! I have watched a testimony of a small merchant store in the NY. The owner has said that he has about 25% chargeback rate on its monthly credit card payments, every month!
That's a huge hit for the owners of these little stores that goes out of their pockets directly!
I can see where this would be hugely beneficial to merchants getting ripped off. I am always weary selling on eBay too, considering paypal now give a 6 MONTH window for disputes to be filed.
I've gone though a paypal dispute, facts dont seem to matter, only their "terms of service". So if you know the terms of service and how to use them to your advantage, its very easy to cheat people on there.