Ebay should directly accept bitcoin payments and then it would be good enough as PP can be charged back but not bitcoins.
I was about to post the same, but then I realized how volatile the Bitcoin is. If Ebay accepts direct payments in the form of Bitcoin or other crypto, then there is a chance of incurring loss, as the exchange rate can wildly fluctuate in a matter of minutes. So it will be better for them to go for Bitcoin-based payment processors, such as Bitpay.
The exchange rate of bitcoins is an issue but Ebay should use a payment processor that is accepted world wide while PayPal ins't accepted worldwide. There are some countries that cannot receive payments via PayPal which is not the case with bitcoins. Bitpay could be a great payment processor if introduced or any other payment processor that can convert bitcoins to USD and save the balance in USD.