well i think u need them both if only working hard only your boss will happy and if you only working smart but no hard working you cant achieved anything and if using both theres no doubt you can achieve what is your aiming for.
I agree that you will need both. Earning money in this world is easy once you have a good network of contacts and good capital, but at the beginning it's a nightmare.
Once we reach a certain point we can move towards passive income and work less, when we have a great amount of capital, and spend more time with family, travel and things like that. It all depends on what you want to do. If we worked hard and smart enough in some years we won't need to work anymore, you will then decide if you want to work for fun or do something else.
I know that the idea of working for fun sounds like crazy for a lot of people, but if you like what you do, then it's not so crazy.