If you employ managers like Ancelotti and Benitez who demand control the there is no point having a director of football.
If you have anowner who imposes his judgment on who the manager should be and overrides the DoF then it renders his role redundant and the DoF impotent.
If , however the owner accepts that he hasn’t got a clue about football and wants to build a young team with a young coach then you definitely do need a DoF , but make sure that it's one who unlike Brands is decent at his job.