I've been using the virtual credit card number feature for my card, and I thought I'd post a review.* For a description of how these work, see this page.
I use a different "virtual" credit card number for each of the merchants that I pay on a recurring basis (e.g. phone, cable, etc.).* Thus if the number escapes from their records, it can't be used (the number will work for one merchant only).
I also use it when buying something online.* One advantage here is that there's no chance that the merchant will charge too much or bill twice by mistake.
I can generate numbers from my credit card company's web site, or download software to do this.* The software (automatically fills in fields, etc.) is poorly designed and slow.* For example, they use a tiny window to display the list of numbers you've used, and you have to scroll a lot).* Also, if you generate a number, but then wait for a few minutes (e.g. on hold) to use it, the window just disappears!* However, it does the job in general.
Another disadvantage is that the max expiration time you get for your virtual numbers is 12 months.* So every year I'll have to extend the expiration (not sure if that will work) or generate a new number.
If my card is stolen I'm hoping that the numbers I've generated will automatically redirect to the new card that I get.
Of course, you are always protected against fraudulent charges, even if you don't use this feature.* But I've decided that it can protect me from some of the hassles I'd have to endure if my card number were stolen.
Bottom line: Worth using.