You have to just make seperate keybinds for things like ambush (shadowstrike) vs backstab.
So what happens when you Shadow Dance now with no bar?
Even though they are more or less same ability just one with a stance requirement. Guess it's just adding artificial keybinds to make pruning look less insane.
Logic of if you prune everything why need a bar ¯\_(ツ)_/¯ . Then again there's still a stealth bar, so blizzard has never understood logic.
Best part is you can't even force the functionality with [stance] macros or [stealth] / [nostealth] macros.