Finally, the SandCastle does something of convenience FOR the customer... and all you people do is bash them.
PayPal has become the "internet way" of paying for merchandise ordered online. I've offered my customers this option for many years... so has my wife with her online store and Ebay auctions.
Other airlines (NW IIRC) are also using PayPal.
For those who don't know what PayPal is all about, let me give you a short tour. Many people are still hesitant about using CC info over the internet (and I can't blame them). PayPal provides a mechanism to pay for things online using a CC without having to directly providing the CC info to the seller. As a buyer, you have the choice of paying with your PayPal balance, your checking account that's linked to your PP account, or the CC linked to your PP account.
And if you have a balance in your PayPal account, your money earns interest as if it's in a bank... usually at interest rates better than money market accounts.