I don't like that they did this.... But I do understand the reasoning.. It'd be abused... For most ppl. PvE marks are more easily attainable than crucible marks.. Yeah trading mats for marks to trade it back is illogical. Accept. If you trade in Vanguard marks for mats to trade for crucible marks.. It's to easy to abuse.. Granted. That's the only way it could be or be used for the player in such a way. But it's so minor. It shouldn't be a problem... I don't see programing wise. It had to be one or the other... But. I hope soon they give us both