Having previously trained and taught using a more combat or skills orientated approach to Wing Chun, I have personally found this method focused around cultivating Nim Tao (primarily through a form of standing meditation), to be both a faster and more effective approach while also providing an ideal vehicle for exploring the relationship between the conscious mind, the subconscious mind and the body; the optimal coordination of which underpins our physical and mental wellbeing while also enabling all instances of peak performance (Wing Chun or otherwise).
While everyone has experienced flow at some point - most simply defined as a feeling of selflessness, timelessness, effortlessness and richness that culminate in a feeling of complete presence and engagement - these experiences are often perceived as by-products of the activity (e.g. surfing, yoga, singing, painting etc.) and are therefore less likely to be transferred to other tasks. By actively cultivating this state of mind using CST’s approach, one can more easily apply it at will, regardless of the application or task.
Once we have learnt to achieve this Nim Tao state and use it to generate force as demonstrated in the What We Do section video, Chi Sau (or sticking hands) is used to apply this relaxed force to the mechanics of fighting. This is not a simulation of an actual fight, but instead a way to practice applying Nim Tao and the body's inherent ability to balance (enabling us to react to complex incoming forces in real time) to deal with incoming force through the arms instead of actively trying to resist or counter it using tension.
This exercise is a continuous and ongoing simulation of the split second when you make contact with your opponent’s arms/body mass in a combat situation, allowing your relaxed arms and body to neutralize their force and deliver your own powerful strike using your entire body mass. In an actual fight your only goal is to strike through your opponents guard to the target allowing you to control/trap their arms and disrupt their balance, limiting their ability to strike effectively while delivering your own devastating attacks. The rolling and trapping only occurs should your strikes fail to land for whatever reason (intercepted, successfully blocked etc. as can be seen in the video below) and happens as a by-product of the incoming force meeting your relaxed structure rather than being pre-planned techniques you need to execute. Like trying to submerge a beach ball in water using one finger, the speed and rolling of the arms (the beach ball) is directly correlated to the speed and force being applied by your opponent and requires no conscious intervention. In many ways Chi Sau is closer to a fast game of three dimensional chess played using instinct, than a form of traditional sparring.