With the way that Gearbox has been rolling out hotfixes, I find it worth holding on to other legendaries in case something I use gets nerfed, or something in my bank gets buffed. Its just such a strange design decision that the game that espouses having over a billion guns, lets you hold onto an infinitesimally small percentage of them; Destiny 2 lets you have max 3 characters and has a substantially smaller amount of gear, and yet your vault space is magnitudes larger by default.