Yes, you absolutely can. I have been doing this primarily to liquidate Disney gift card deals I collect on a regular basis. You do have to pick which contract you’re paying on - I just try to keep it balanced between my contracts based on their point ratios to other contracts.
Yeah, I had a 10% offer on Disney Cards through one of my credit cards and grabbed a $500 Disney Gift Card and just paid it on-line through my account. If you go to the dues section you can see the credit on your account.