I think they are not entirely useless, as they (again) give their stats now when equipped, I still have a few kept as a memory, since you can't get them anymore. However the last ones which were available are on Altar of Malice tier, and older ones are even more useless, there are stronger purple adorns from Terrors of Thalumbra, and Kunark Ascending now.
IRubick I remember that name You have been around awhile. Thanks for the reply. So just sell them to merchant?
The merchant likely won't give you anything of value. I'd personally keep something like that for nostalgia's sake.