AFAIK, Paypal offers buyer protection when you actually ship a physical item and the parcel can be tracked.
So if you send a paper wallet with parcel tracking, the buyer can not successfully do a chargeback, because Paypal and ebay know that your shipment is registered.
Also you can disable the possibility for the buyer to return back the item.
I hope it's not that Ebay/PP are against cryptocurrencies, they just can't protect the buyer when he's not selling a physical item, so this applies to all virtual items, even passwords, domains, accounts, etc.
Then solve the problem by just sending a paper wallet
Could it work ?
This is a good idea because sending a paper wallet will not be able to make dispute in PayPal