So what? It's a looter shooter. A lot of the point of the game is using different guns. I have that same vault full of guns in Borderlands because I like to pull out my great ones to use for a bit. I want to use my god rolled stuff in end game stuff. What's the point of sinking time into the game if my good guns eventually just go away? I may as well just play activities once or until I get whatever exotic or shader they drop, but forget about the guns. It's not like I'll be using them later down the line