the training purpose of tangnibu

[.Q.]

Tangnibu helps to train how to maintain structural connection while moving. Once you build the habit you don't have to walk via tangnibu in order to maintain structure. It's also used to train certain footwork that require good ground sensitivity. It's designed to be harder than your actual need for combat. It's the same concept as walking around with ankle weights. You don't go into the ring wearing them.

[Trick]

Honestly, I see more of Pencak Silat in Baguazhang than anything...

You've got Silat, I've got Mongolia, Scott P Philips has Nezha and his firewheels.... there are only more questions

the vikings, it was the viking explorers moving eastward that inspired the easterners to come up with their bagua https://gnosticwarrior.com/the-helm-of-awe.html