I don't see it. There's an added step (exchange) for anyone wishing to transact in Bitcoin compared to just putting their debit/credit card details in to such a

I don't see it. There's an added step (exchange) for anyone wishing to transact in Bitcoin compared to just putting their debit/credit card details in to such already respectable sites... and, if anything, you want more reversibility when dealing with sites you don't trust so much, not less. For this reason I don't see Bitcoin exploding based on its utility as a payment platform, at least on-line. Fiat NFC mobile payments can be made just as convenient on the high street as well. IMHO Bitcoins success with the everyman really hinges on being a super convenient but secure alternative for casual payments.