The techniques of aikido are used to develope aiki but are not for self defense. Therefore aiki is not for self defense? If aiki is for self defense then why can't you put aiki into the Aikido techniques and have something?
Well, you could - that is what some people try to do. But the Aikido techniques themselves are insufficient for self-defence. If I were young again I would spend my life first targeting aiki
and then trying to put it into Judo/Jujutsu etc. I did try ... but it took me too long to figure it all out. Too old now. I was led down the wrong paths until I eventually broke free for myself.