It's a combination of not having the vault space to store everything and re-rolls and it applies to both shaders and emblems. I pretty much deleted all my trials, queen and variks items and due to re-rolls and general lack of interest I currently dont have the rank and/or interest to get them back. For instance, I'm too low in rank to re-buy the Variks shaders and I'm certainly not going to spend hours finding people for PoE and then farm it. Nor am I playing trials anymore.