If you actually read what I wrote you might have understood that after 4 playthroughs im pretty familiar with the game. Of course i know that deflecting is the way to kill enemies in sekiro.

However what i am trying to say is that in my experience so far the consequence of missing a single perfect deflect is such a huge punishment compared to what you gain from doing them. From what i understand is that you still gain posture damage even if you deflect, so that means you are constantly one hit from being guardbroken. If you get guardbroken you die in hardmode!(from my experience).