I am not trying to be snobby,but as you said for my situation,KKW/WTF stylist, any other paper does not tell me anything.No offense intended, but that's the exact kind of snobbery that can be off-putting. It should suffice to say that KKW certification is relevant to YOU because it can be a measure of sorts for the physical skills important to YOUR practice of TKD.
Others can and do find differently, in which case another certification (or even none) might be more preferable to them.
I have had many bb's come to my school, we used to be the only TKD around, from ata itf and joe's tkd,each had certification but none new the same requirements.Even the same certificate (example itf) would not mean the same,some bobbed up and down some didn't,some hissed some did not.They all could fit in after a while and worked to get their KKW but it was not like a KKW certified BB came in the door, family member!
By the way this could be another thread but BB'S from other schools are a pain to train.