Or, they may simply have an idea you don't. It might be better, worse, or just different. You don't get to say whether someone finds a value in using that to teach a concept different than what you've seen it used for.Others within the same system may not use biu sau to teach a punching idea because to do so would be nonsensical. I guess they could go insane and do it, or fail to understand the system and do it, but that's about all. Certainly no value in it.