What I find the most important part of this article is not 'how can we use our thoughts to create habits,' but instead 'be more aware of the thoughts you have - are they the thoughts you want to become word and act?'

I think that's one of the most powerful messages of the quote. A thought doesn't have to become word or action, but an unquestioned thought, a thought that is allowed to determine what kind of person we think we are, is much likelier to become word, action, habit, character...etc. Whereas if a thought that is stopped in its tracks and corrected, then it will stop there. And yes, that has a lot to do with asking 'why'.