Saw this, and it felt a bit like gatekeeping. It's the most powerful form of qigong out there, and is not locked behind an academy paywall and a guru-like teacher.
I switched now to just standing and nothing else on energetics. 40mins in ball holding pose, as recommended in Marc Cohen's book Inside Zhan Zhuang.
My body becomes more supple, looser as the time progresses, not harder or stiffer.
An important part of that is body scanning and allowing knots of tension to release. There are experiences when tension and hardness suddenly dissolve, after which the body feels light and soft.
I would advise trying it for yourself. If you feel stiffer and more stuck, as Damo intimates, then switch to wuji or moving forms. But don't take his word as gospel, without trying for yourself.