Also, being able to store a massive amount of materials would make it hard for them to control the game economy. I.e. If a new set of weapons are released they want people to work this content over time, not gave what is effectively a vault of cash save and then have these people get bored again and want more Edit: this is now relevant because people are now rewarded with mats for doing bounties and the like, but they can't increase the price of crucible items because it is set for people who actually play crucible