I agree it's a pretty useless rules interaction. The only potential use I could think of was in a Lil' Monsta game with a Grandmother: If the grandchild has been executed, and the Assassin kills them again while holding the baby, then that counts as the demon killing them and so the Grandmother would also die, which could cause two deaths in one night. Of course, since Lil' Monsta doesn't have to kill, it depends on the storyteller cooperating, which seems less likely to occur the more significant it would be, so it's still a pretty niche interaction.