I think that it is a good idea to reminds ourselves of what are practical techniques and what are traditional techniques. All have their uses. None are useless. Most are derived from sword techniques. Some have evolved to a point where this is unrecogzizable, some you can still plainly see the origins. Some have evolved into very practical techniques for "today's mugger" vs. an enemy samurai.
I think what is pointless is to practice aikido with the mindset that you are only trying to perfect and practice how well you can defend yourself in a fight. With this belief, then you are forgetting or ignoring the spiritual and character building aspect.
Being technically effective in aikido is great, and to those unfortunate enough to be placed in a situation where you have to test it, useful. But, that is not what aikido is about.
Technique is the vehicle used to attain improvement in the spiritual aspect, and so that's why we start training with technique and form first rather than strictly lecture and meditation. But why concentrate on just how to use aikido in a fight?
And besides, kokyu is used in all techniques. So how can the practice of kokyu be useless, as in kokyu-nage?
Good training to you.