Working hard is different from working hard. Working smart is the act of using your brain to lighten your work. While working hard is your focusing all your strength in that certain work.
Well what's the difference though if those both workers are same income or profit? , For me it's better to working smart to have strategy , but I think it's the same though you will need to exert an maximum effort on the job you're taking, to have a better income, so I think there is no difference on this two.