My teacher said someday (if i am understand hem correctly) that there is a difference between Aikido and self-defence. Sure you can use Aikido techniques in a real fight but then you also can apply additional techniques if you want to. Then it would be self-defence. For instance uchi kaiten nage omote. To apply an additional knee in the face would be very easy but not very harmonious. but then again maybe i do not want to be harmonious in that fight. Then it is no Aikido.