Ascendant raisins... Slightly wilted celery... They're just trolling us. It's probably a bet to see how rediculous they can get with these useless items and us still hang on to them! Next it will be slightly stale pita chips or something.

The current purpose of the coupon is unknown. Data miners have found a legendary version of it but we have no way of knowing how or when we get it. For now you should keep it in you until either someone finds out if there is a secret or until the datamined legendary version has been classified as a trick by Bungie.

The obvious. Dismantle it.