From 1st Jan 2009 rewards point you'll earn are to reduce

On silver credit cards you will earn 1 point for every purchase or swap for Rs.200 instead 150, now.

On Gold credit cards you will 1point for every purchase or swap Rs. 150 instead Rs100 now.

You can redeem your points for a gift an additional Rs.75 handling Charges will be applicable.

Makes me think is it really beneficial to use Hdfc cards at all?