Totally different games, I screwed up. 
Thematically they are the same, and structurally they are similar games. But the “One Night” version is shorter and simpler because you don’t got through multiple nights eliminating players. As a party game Ultimate Werewolf works well because people can get eliminated and go do other things and come back later to spectate. Because of the elimination aspect you need quite a few participants for it to work well.
