My teacher trained extensively with Zhang Zhijun (the focus of the video). His extremely detailed perspective on spiraling serves to both weave the body together (how many people are going to post "d'uh") and provide a method to work around "bracing" -- as a result, large groups of muscles fire together. Sort of a consequence of his "fingers move first" methodology.
I'm certain other people accomplish the same thing in other ways but interesting to note Zhang Zhijun's Chen taiji is not the same as Chen Xiao Wang's, Chen Zhenglei's, etc. Also interesting is that he had more hands on time with Chen Zhao Kui than anyone else.