With regards to weapons that do death damage, you really only need to worry about Accidentally healing Wraiths, Ghosts and other spectral undead with them. Skeletons, zombies and mummies are affected normally.
For me, personally, I would like the opportunity to reclaim a lost unique item. Wether it be a one-time purchase at exorbitant prices from some shady merchant in the sewers of New Garand or some back alley in Freetown, a rumor boss drop or some other method.
Also, not everyone reads the description of something before they sell it off. If it looks like some other, more common, item you wouldn't think twice about selling it off. Especially if you have a bunch of the more common item in your backpack. When selling stuff I am usually on "auto pilot" and don't always pay attention to am item's description/name, I pay attention to what it looks lke, though.