I'm new to this whole bitcoin thing, finally got my first fraction after waiting a week through coinbase.

I don't understand why selling bitcoin w/ PayPal is high risk. There is the blockchain record of all transactions, so if I want to sell on eBay, I would instruct the winner to send a note in his/her PayPal payment of their wallet address and maybe to include some statement such as "this is a unique wallet address, public bitcoin blockchain record of payment to this address is agreed as proof of delivery".

Am I missing something?