Sbi card point are worthless of all I have seen. Take for example silver credit card.
You earn 1point for every Re.1 spent. Minimum you an redeem is 1000 points for Dominos or cafe coffee day gift voucher of Rs.200. That means each point in worth disappointing 20paisa. On top of it you have to pay Rs.99 fee for redeeming the reward point.

Rs.200 voucher = 1000points + Rs.99Redemption fee= Rs.100,000 spent via credit card + Rs.99 redemption fee.
On top of it you pay Rs.250 annual fee on this card as Sbi Silver Credit Card is not free.

And remember SBI credit card day to day operations are run by GE Money.