Well, while reading at it. Bitcoin had been a challenger to paypal. Which is more useful and highly digitized currency now? What do you think or which do you prefer? 
Can BitCoin replace X (insert whatever payment form/currency you like here)? No. At least, not at this point. When transactions for speculative buys (investments or essentially day trading) range thirty times higher than transactions from actual utility (buying merchandise) by many estimates, the market is simply too volatile. When something halves or doubles in a matter of days, there cannot be confidence in it to lead to mass adaptation. Can BitCoin someday find a (likely large) following, and potentially displace some heavyweights in the payment/currency world? Absolutely. But it wont, until it stops holding value based on speculation, and starts holding value based on utility.
I totally agree that bitcoin price is too volatile now to be used as a currency. Most of the sites accepting bitcoin now are in fact using bitpay or coinbase to immediately convert the bitcoin payment to fiat money.
Btw, where did you get the 30x estimate?