When you are only working smart, chances of success are high if you have enough luck to turn things under your favor and working hard may only make you stronger in that field and not rich. So, according to me both aspects of working hard and smart should be taken together. Success and fortune can't just ring you door bell, its like wining a lottery ticket where chances of wining are very low. So, for achieving success and fortune one should work hard with smart brains to stay ahead of everyone in their field.