Again I cant help but feel your looking for reasons to justify your investment in long lonley hours of stance training.
Your entitled to your opinion. You don't know much about me, my training background, training habits etc. so you make a lot of assumptions. Not much to be done or said about that.
But its the muscles that your generate the force,
...and the structure that amplifies it.
and there is no reason that you can not work on posture while doing weights. Why is posture a stance thing? Shouldnt we be working on good posture all the time?
Not "posture", "THE posture" ie. the stance. There is more to a particular stance than just set your feet paralell and squat down. I'm talking about form. The proper alignment of the lumbars, the appropriate curve of the chest, the tucking of the tail bone, the folding of the pelvis and more. There is no way to use weight training for instance to give you a good san ti shi or in my case, the Baji "ding zhou shi" and my other favorite for supplementary training, the "fu hu zhuang".
Getting back to your previous coment about "wasted" time. Don't forget we...er . . I am talking about supplementary training. Not the core really. For me it's usually 1 of several cases when I do stance training.
1. At the end of a long workout. Like on Sundays, I have a 40 minute bike ride followed by a roughly 3 hour practice. At the end of that 3 hours I am typically too tired to keep practicing my other stuff. So to keep going I will often settle for some stance trainng.
2. When I get interupted in my training and someone needs to talk to me about soimething, I'll keep the low stance while I chat. Or at home it's one of those things you can do when watching TV. I fit it in in those times when I have no space to train like in my office at school between classes or on my lunch break which is 2 hours long. Sometimes I even train in restaurants here. At lunch with Shifu, while we're waiting for other people to arrive or for the servers to show up, just lifting my body weight off the chair. Not enough for everyone to see, just support the weight but leave your but touching the chair.
3. To correct errors in my form. Find the spot where you lost your balance or felt there was no good power or wherever you think your form needs improving and hold it there for as long as possible. A lot of this happens when getting instruction even in applications. You do the move and teacher yells "freeze!" and starts to make corrections. He might start giving some explanations as well, showing you where you are vulnerable or discussing some potential coutnerattack at this point in the move. So you take it all in but generally don't stand up and relaxe during the lecture part of your class.
Why would you want to make your self less mobile when fighting taller people?
If you have done some decent stance work then you won't be less mobile.
*sigh* but I think you have already made your mind up on this one anyways.