tbh: 5 weeks ago I messaged one of these guys on ebay to negotiate a better price for 4 arduino nano clones by going around ebay (I know, against ebay policy). He made a good price and I paypaled the money. No product arrived and no communication. I must say I'm glad he didn't take bitcoins. Now I can do a chargeback on paypal (hopefully they wont notice I violated eBay policy)... not possible with BTC.
Bitcoin technology contains more complex forms of transactions, for example, transactions with a third-party escrow function. We are currently not using bitcoin technology fully.