Despite appearances, Facebook is not impartial to this question whatsoever. They would profit greatly from keeping dead people's profiles on their site.
Maybe "greatly" is too strong a word but it definitely helps to cement Facebook as the clearinghouse of memories, both for the living and dead.
Not sure if they would profit greatly, because they can't target dead people with their ads.
Loved ones and friends still respond strongly to the presence of a dead person. In fact I wouldn't be surprised if friends of dead people incur more engagement than people when they were alive (sadly).