An interesting question that for me highlights how there's too much emphasis on retail acceptance of Bitcoin.  Which doesn't matter much.  Taking bitcoin payments isn't any different to any other currency, the retailer is just offering payment through a third party provider.  When i go to a US or European site they offer the same for my £.  They dont want my £, they will have the payment processed and given in their local currency.

Really, there's not much advancement of Bitcoin until it is wanted as the currency, until it is used for direct payment of goods and services.  Until Nestle takes payment of Bitcoin for a delivery of a shipment of chocolate or baby milk; until BP takes payment of Bitcoin for a shipment of lubricants.  And then holding them and using them to pay their payments to their supply chain that use Bitcoins.

Online retailers accepting bitcoins are just exploiting a self-publicising niche market.  It generates some headline and gets a few $'00,000 through the tills that might have gone elsewhere or more likely not spent.  Theres not real economic growth as those BTC just go straight back into the currency exchange market.