Ya I was wondering the same thing, but yesterday I noticed it only would shine when the in-game time was set to night. E.g if the map was daytime it wouldn't shine, but if it is night time in real life and you return to orbit, the gear will shine. Also, if you are loaded into a night version of a map, it will shine there too. I would greatly appreciate if Bungie gave us the option to equip the 'shining parts' as ornaments so we can choose to have it on/off at will. Lastly, it would be even better if Bungie gave us the ability to re-roll the gear via some consumable or picking it up from the holiday kiosk, because it would even further incentivize the purchase, and make it more far to those who have allready made the purchase.