I am not trying to be stubborn here, but why not just practice the techniques that are supposedly "hidden" within the forms. The basic argument I have heard for a long time supporting forms as integral to being proficient in TKD is that somehow hidden within them are practical techniques/sparring techniques/vital techniques.
There are a number of answers for your question. All of them can be true or none of them or some of them. Take your pick because ultimately your TKD is exactly that: your own.
1) You practice forms because many teachers only know the form. They do not know the applications and therefore they can't teach them. Nonetheless, the knowledge exists there in the form and can be extracted when the student is ready to start looking for them. Bunkai analysis is a learning tool in of itself as you learn to look for principles of execution rather than just memorizing rote techniques.
2) You practice forms because you are studying a martial ART. If your only concern is fighting prowess, I daresay there are shorter steps to that than TKD or karate. Forms are among the biggest artistic elements in martial arts. As evidence, Shosin Nagamine regularly taught and practiced Okinawan folk dance in addition to karate, since he felt the two had synergy to each other. It's been said that if you're not doing kata, you're not doing karate. I agree with that statement.
3) You practice forms because they are an awesome tool for training by yourself with no equipment. What if Tom Hanks from "Castaway" had been a martial artist? You can bet he'd be working his patterns from beginning to end over and over again.
4) You practice forms for the self-improvement aspects. Kata has been described as moving meditation by many in a variety of books and articles, some of which you can even read via Google. I buy it. I don't practice kata and karate just for self-defense reasons.