Not if the seller proves the description accurately described the product delivered..
So we're right back to where we started. The buyer says the product wasn't as described because he didn't get the promised BitCoins, he only got the certificate. If you say the buyer gets both a certificate and BitCoins, and the buyer says he only got the certificate and sent it back, then he's saying the product wasn't as described. So you're back to having to prove to PayPal that he got the BitCoins.
Actually this would work for PayPal. I believe PayPal doesn't get involved with SNAD disputes and asks you to resolve it between the buyer and seller. However it wouldn't work for a credit card chargeback.