Card Verification Numbers (CVN), those 3 digits on the back of a Visa, MasterCard and Discover Cards and the 4 digits on the front of an AMEX should be taken advantage of.
Aside from the confusing acronyms from each of the card brands (CVV, CVC, etc.), their time has come. When they first arrived on the scene, consumers were confused and this may have led to some abandonment. Now it appears, that merchants who do not ask for them may be risking abandonment.
While far from perfect, and nothing is, there is no question that successful authentication of the CVN does provide significant fraud prevention and remediation benefits.
It is true that the card skimmers of the world now capture the CVN too and when card numbers are sold on the Internet (or in some back alley), ones with valid CVNs fetch more dough. As with all fraud prevention and remediation efforts, you have to take advantage of multiple layers.
In the physical world, the holograms that are applied to cards were counterfeited within weeks of their introduction but it is one more thing the bad guys have to deal with, it increased the cost to commit fraud and continues to keep the casual fraudster at bay.