I feel like it needs to be used either for rep or for marks due to the difficulty (in comparison to other mats) in obtaining it (i.e. either nightfall, hard prisons or trials packages). I mean, I'm only asking because I have about 30 sitting around, having upgraded everything I need to. ascending for the crucible doesnt really make sense seeing as damage is irrelevant, and i think going forward all the original content will need to be revamped to fit the play model of the new content, so they're still going to be subpar compared to the rares from the taken king. It'll be interesting to see. All I know for sure is that my PvE K/D is going to plummet once I start running nightfalls with a sword.