Maritime reverse thrust is in most cases called reverse gear for simplicity. It is rare and sophisticated vessels that have VP props.
Bow thrusters point perpandicular to a ship's axis to move the bow sideways to aid manoeverability ... they don't point the way a ship is going.
My limited knowledge of reverse thrust (as an SEP cessna driver) suggests that I, for one, would like to keep full control of my thrust and its vectors by explicitly reducing thrust then explicitly selecting reverse when needed. I would not want something armed that could spoil my day in the event of a late go around.