Bitcoin is good as a "Alternate payment system" but it can't replace CC system as people are using it from a long time. Both have some advantages and disadvantages for merchant and consumer.
I have a feeling that these big merchants adopting BTC as a payment platform are going to be largely disappointed by the lack of people who use it.
Well no, they will only get disappointment if they will start accepting "Bitcoins" Only. If they will chose to aceept BTC on their sites along with other payment methods, they will get more consumer traffic. (Bitcoiner).
Why would the consumer buy BTC to pay for something when he could just use his CC and make money?
It's true but isn't that's comman sense? If someone have Only Bitcons (Or extra btc) he will obviously use bitcoins for payment and if someome have CC (and good cash in his bank acc) he will use that.