I tend to look at this differently.
Paying with credit card is essentially no more than saying that company X will pay you on my behalf. Subsequently, company X will come to me for the amount paid increased with fees/interest.
The same type of construction is possible with Bitcoin. Company X will pay you on my behalf, but not in USD but BTC instead. Subsequently, company X will come to me for the amount of BTC paid (or USD if agreed upon) increased with fees/interest.
From that perspective, speaking about credit card payments on the one hand and BTC payments on the other hand is comparing apples with oranges.
The more I think about it, the more it dawns on me that BTC's essential property is really ease of payment. Not the software, not your HDD rumbling for hours, correction, days without end to update the blockchain but the pure and simple fact that I can send 'something' to anyone, even the moon (figurally speaking) if an astronaut has some sort of Internet connection. In fact, an internet connection is not even required for the receiver for the payment itself. He can generate his own unique key throuhg brainwallet.org or similar algorithm available offline to send BTC to.
The purse simple fact of a payment requires nothing other than me, my internet connection, the Bitcoin protocol and a receiving address. No blockades, no interference, nobody skimming fees in between and holding up one of the most simple and valuable things on earth: exchange between humans.
In a very abstract way of thinking about Bitcoin, everything that was not possible due to payment frictions, is now possible due to Bitcoin. Just to round off this little brainstorming event, a lot of things are alread possible:
*electronic money
*mobile money
*international payments
Not considering its flaws, Paypal is already immensely usefull due to its property of easy online payments outside of the banking system.
Very rough, Bitcoin enables the following additional properties:
*virtually no fees
*receive electronic payments without a bank account/Paypal account
*no central control
I do not see myself paying with BTC at the grocery store due to BTC's unique properties. But the same properties make it immensely usefull to make payments all over the world/universe to anyone, literally anyone, without limitations (if waiting for confirmation is not a problem; exactly the reason why I do not see it happening for BTC at the grocery store).
It is already possible to purchase the most outlandisch tablet from the most remote tablet factory/seller from China. Within time, you can also pay the chap without limitations.
Trust is not the problem (its a topic of trade as long as people have existed). Ability to pay/receive is, at least for a large part of the world (not our 1st world). Let's wait for smartphones and mobile internet to break through in developing countries. From where I am now in my line of thinking, that will be the most important source of BTC's upcoming success. Secondary properties (such as the fixed amount of 21 million BTC) are helpful (e.g., for the 1st world users).
It's gonna be great