Keep them out of your home at all cost, because they will steal your sim's things. What I always do is if I discover that one of my sim's friend has that trait I will go into mange world, and turn on the cheat that will allow me to change their traits in CAS. If I discover a sim has that trait and who is not connected I will actually delete that sim from my game. Even their ghost will steal your sim's things if given an opportunity. When the trait first came out, I tested this with my own sim, and she would not stop taking other sim's belongings.
About the only use for this trait in my mind would be for storytelling purposes.