I'm not talking about it's function as formal demo gear. Rather I wish to know about the Hoi itself.

What does it add to the art? When did Shorinji-ka (or do you all prefer Kenshi) start using it? Why is it the color it is? Why do I see some people wearing cloth belts, and some people wearing rope belts while using a Hoi? Is it meant to make the practitioners look different from Karateka? What does it mean.
Is it intended to mimic a Japanese monk's black robes? Cause it kinda looks like it.

Sorry if these questions have been asked before and for being nosy, but google wasn't helping and I am curious.