Why on earth would I as a purchaser want to buy something with bitcoins (which offer me no protection) instead of using a credit card (which offers me extensive protections).
As a merchant when a customer chooses to pay with bitcoin I pass on the savings (that would instead go to middlemen like paypal and credit card companies) onto the customers, and they love it judging by feedback received.
Credit card companies and paypal etc are parasites who siphon billions from global commerce, their business models are based on old money transmission methods.
There used to be a time when people would ask as to why they would use credit card over cash, yet people moved on and accepted new concepts and technology
http://www.cardfellow.com/blog/charging-customers-a-credit-c...
However, when it comes to physical goods costing more than a trivial amount of money, I'd certainly want to use a credit card.
What about if you amortize over the time it takes to set up your bitcoin wallet, etcetcetc. (and to be fair, it takes time to set up a credit card, but there's also a much larger set of purchases to amortize over).
There's still a significant learning cost, of course, but I'm encouraged by how much better the infrastructure around Bitcoin is compared to just a few years ago. The infrastructure looks pretty professional now, and the security practices are noticeably better (though that isn't exactly hard, considering how insecure the earliest services were!)