Sal Canzonieri discusses the importance of body posture briefly in
one of his early writings:
Now - in the article you will see he mentions that there are nei gong methods that are found in most Chinese arts, which assist in this postural alignment. Since it is very hard to correct people in motion, standing post exercises are a great way to utilize this posture-adjustment function.
Although the english translation below could use some further details, Master Shi De Jian, a former XingYi, pigua, Bagua, Chen Taiji practitioner (now Shaolin Monk) explicates the basic idea of Xu Zhuang, (meaning tranquil standing), shaolin most basic foundational Zhan Zhuang:
While he recommends five to thirty minutes, I personally found that 30-1 hour in my beginning weeks/months was instrumental in some of the greater postural adjustments and other benefits I received. I've been at that (consistently daily) for a couple years, and when I have time do it considerably longer (30-1 hour) as mind practice. My knee health has improved, although it is hard to say if it is only related to the standing or moving/stepping practices (likely both).
As to the other part that Sal Canzonieri mentions- respiration regulation, I don't know that Sal was specifically referring to breath practice/breathing practice, but Master De Jian also explicates various natural breathing practices that combine these practices.
My understanding is that these can aid in the goal of bringing the mind to an "extreme point" of focus where all distracted thoughts are stilled.