I can see what you mean as I also started off doing Karate and now do a traditional form of Kung Fu.
Firstly about the low stances and more importantly what you were saying about doing it as a discipline and fitness etc and not for fighting: Kung Fu was originally created to train the mind to focus and develop an inner strength of the mind and the self defense and fighting aspects all came later so the low stances eg Horse stance are meant to focus your mind and train both your muscles to endure more then they have to and your mind to be able to overcome pain and the distraction of muscle tension enableing you to focus on the task at hand.
What I mean by training your muscles to endure more then they have to is similar to what other people have been saying. You're not going to have to go as deep into your stance in a real fight as you do in your training but the concept is if you can hold it in such a deep stance then when it comes to an actual fight where you're higher then it should be significantly easier to keep your balance and move around quickly.
The other thing you said about bouncing is interesting as we were talking about this in class yesterday. The concept of bouncing is so that you can move quicker which is true but bouncing tends to happan in styles like boxing,
karate, taekwondo etc but if you watch styles liek MMA, wrestling, jiujustu they don't bounce because they have to be wary of the take-down. This is why Kung Fu doesn't bounce especially in tradityional styles as it's based more around actual fighting rather than sport which is why San Shou (modern sport version to traditional Kung Fu) looks completely different as you'd get disqulified for tiger-clawing someone in the face or grabbing an opponents special bits. So they're all good techniques but they're all for different things which is why you can never compare different MA as they're all used for completely different things.
K that was a bit of an essay but I hope it helped...any other points you want to know about then feel free to message me and I'll try to do my best :)
Li