Virtual Account Numbers

Ive never used them or even heard of them, however I can see a couple of advantages:

You could generate a one off account code that is valid only for a set period (maybe a day or week) just long enough to process the order then it is invalid. If this code was stolen then it would soon cancel itself

Also if your number was stolen you could easily shut it down through a control panel and geenrate a new number instantly rather than cancelling your card and waiting for a new one to be issued.

The downside of course is that all shopping sites would need to support the virtual accounts.

The number itself is going to be no more secure, but in the event it does get stolen it can be deactivated easier...