It's not great in many respects, but it has the compelling advantage of shifting fraud liability from the merchant to someone else. Depending on your market, it

It's not great in many respects, but it has the compelling advantage of shifting fraud liability from the merchant to someone else. Depending on your market, it may be worth the loss in conversions from activating it. Even if you're in a normally low-fraud market, as every business I work with that takes card payments is, almost anyone taking small value card payments on-line is vulnerable to being used as a card testing engine if their system can be automated. If nothing else, being able to toggle the extra check on temporarily if you become aware that your system is being abused that way is an extra level of security you can apply in a hurry.