Yes, the Ultimate Game Card is still usable. Let's say you have a $20 U.G.C and you want to purchase a starter pack. All you have to do is login with the knight of your choice, click the CE Icon on the lower right. Then select the package of your choice, and click "Other" from the payment options. This should bring you here.
Then click the ">>>" on the far right on the product you want. Then you should see more options on payment methods. Click "Pay By Ca$h". Select "Ultimate Game Card" and click continue. Enter your details, and click continue. Follow the steps after (Sorry I haven't payed before) until you see a prompt to enter your card code, and enter the code on the back of the card. After you have finished all this, wait a moment for your package to be given to your knight. Log on and viola! Your things should be there! Hope this helps,

~ justalexp