How do you propose paying someone without exposing your Bitcoin wallet to the possibility that it could be stolen? You basically have to load your wallet onto some computer, and if that computer is compromised, you lose all the money in your wallet.
Credit cards are a much better system because they are designed with the assumption that you will be compromised and the system is set up to minimize the damage of a compromise.
Perhaps like http://www.bitcointrezor.com/ - a keychain fob which lets you pay and recieve bitcoin safely, even on infected computers, as the private key never leaves the device.
Bitcoin's in its infancy so people currently using it are doing so 'on the metal', but the system is flexible and user friendly layers will be built with time.
Also, reversible payment networks can be built on top of a non-reversible-payment foundation, but not the other way around.
Your wallet being compromised isn't the equivalent of your credit card being compromised. You don't hand out your wallet to people and trust them with it, you can keep it safe and secure.
Credit cards aren't designed to be compromised, they've just accepted that they can't do anything about it and worked on controlling the damage.
Credit cards are a much better system because they are designed with the assumption that you will be compromised and the system is set up to minimize the damage of a compromise.