I've seen it the other way. We've had a few professional dancers come into my dojang and they pick things up immediately. Dance teaches you control over your body, and these ladies had really good balance and posture. It was easy to teach them stances, forms, and kicks. They taught us a thing or two about stretching.
I see the same thing with tricking. Learning how to do a 540 hook kick has improved my regular hook kicks. Learning the 540 roundhouse kick has improved my tornado kicks. However, when I was teaching these to my demonstration team, I asked them when we would use these kicks. They had different answers, but none of them were right.
- "Self defense?" No, too slow for self defense.
- "Sparring?" No, sparring you have to be even faster to get the points, so if it's too slow for self defense it's too slow for sparring.
They couldn't figure it out until I told them "because it looks cool." You do these techniques to show off, because they're flashy, but they don't serve an actual purpose. (Although I have used a 540 back kick in sparring, but that was a little bit different).
Now, training these techniques is not a time-effective way to learn to fight. If pure fighting is what you're about, then these aren't worthless, but they aren't worth enough to be worth your time. They're fun to do, they do help you hone the root technique you're working on, and as
@Headhunter and
@gpseymour mentioned, they are good exercise (or you do good exercise to get your core into shape to do them).