I'm sure you meant BS 6K... it's meant to interrupt, and there are some nasty tech traps off it...
A+K is good at the end of the opponent's combo string, unless it's an uniterruptable string... it can really only be punished by 2A, or talim's 1B etc, it puts you at -14 in FC, ussually its a "what the hell" moment too...
4A+B tech traps off a couple moves after you teach them to get up, but its -9 on hit, so if they aren't blocking after they get hit then they're either mashing or they know what to do about death rose... did not know it could be done from OTG...
BS WR K at least gives advantage... if it was mid it would see more use, and I'm not sure but I think it tech traps off something unless I'm thinking of BCR K (which gives KND on Hit and CH)...
BS 7A at least tech jumps and its useful for teleport moves in a way...
I think The-Instigator explains 22/88 A+B the best, lame joke and all, its horrible but can dodge complete vertical strings, so it has 1 use, and until we figure out the mystery behind "mystery dance" we'll never know if it has another...