Sounds cool but dont sell coins via paypal, you probably will be scammed
That's the next change PayPal/eBay must make:
Accept block chain as proof of transfer to stop these kind of scams.
Scam is not executed via: "i did not receive coins", it's executed via: "someone stole my card and i did not buy that stuff, pls refound me". And Paypal is well known as provider that is always on buyers side....talking from personal expirience.