The reason for the stance methods, and the low stance methods is not (in our line) solely due to the common talking point that it is for strength, or even the very true point that it develops root.
In our line it really IS for developing root, but what is that root for? It is certainly for martial usage, but it and the leg methods/shapes also have an alternate purpose.
This is related to the energetic/medicinal design of the art. Just as the shapes of the arms determine energy flow, so do the shapes of the legs. Similar to meditation sitting methods, the stance methods and shapes of our art create and determine specific energetic (and physiological) body states and actions. These are of course very useful for cultivation, but they are also directly useful for martial arts as well.
These specific energetic and physiological body states created by stance work create the possibility of middle and upper body activities, making applicable JINs possible that otherwise cannot be achieved.
Every time the stance shape changes, it influences the body above it. In Taijiquan our movements are connected, not necessarily solid or unitary but connected, such that the character and energy of the shape of any extremity will influence all of the rest of the body as well. If one thing is off, all is off, if one thing is strongly correct all will be influenced. This is especially true of the actions of the lower body.
Chen Taijiquan in our method starts from the earth and travels up. All activity is determined by connection to the earth and the shape of the connection and conduit traveling upwards. Beginner students start with developing this lower body action, the HARDEST aspect to master, first, and continue for many years. Due to the slow pace of development in this area is usually appears that beginners are starting with upper body choreography, because that shows simplistic progress much faster.
Many people think the ‘secret’ to qi cultivation is in ‘relaxation’ or ‘intention’, but in our method we look to to earth first, then look to the arrangement of the lower body. Both the upper and lower body may look rather ugly for some years, but the intense cultivation will already be igniting with proper attention to lower body yogas, influencing all activity above and in future development.