New Orleans has no supporting cast for Davis and he was getting beat up playing center. Cousins instantly becomes the Pelicans 2nd best player and maybe the best frontcourt in the NBA. A free agent might consider joining them with two all star front court players.
For the Kings, you have a poorly constructed roster with limited upside. They might get 2 lottery picks in this draft and they already have a couple centers in place to replace Cousins. Most importantly, they get rid of Cousins' locker room presence and stranglehold on the franchise.