What the hell is with bowser jr side b

okay, I decided to mess around with bowser jr and his side b might be just ABSOLUTELY BUSTED

it's a cancellable burst option that has a kill confirm and basically give you a third jump??? what the actual fuck? AND IT'S STRAIGHT UP A KILL MOVE TOO like I've messed around with it and it just feels so bullshit, and it's funny because all the bowser jr players I see spam down b and neutral b and RARELY use it even though it just might be the most op thing on his kit