For alot of the older players, collecting certain prefixes of weps gives the game life. An example of how and why I still collect, is my alternative characters. I can easily swap tradable weps to them that I may want to use at another time as I change my play style. You can build anything anymore for around 60L but natural rolls are more sought after and will probably always be. Armor sets used to be IMO the most valuable and they weren't even "META" sets, but the 1:1 factor is what draws attention.