Materials should never be used to buy something earned in PvP. I made a post stating this fact. Now that it is easier to purchase 20 materials of a specified amount it would cheese the Mats for Marks system. I suggested that Factions (Not counting Crucible) should allow individuals to make Purchase with BOTH Vanguard Marks or Crucible Marks. Seeing as Factions dish out missions on Patrol it would make sense from a PvE stand point. This is a far better compromise that should be implemented asap. I hope you can all agree.