I think hard work gives experience & smart work needs experience. Clearly we should do hard work for experience and then use that experience to do smart work.
Sir I will try to explain this with analogy with one statement.
We always say " Practice Makes a Man Perfect ".
But what I will say is "Perfect Practice Makes a Man Perfect".
Sir just practice is Hard work and perfect practice is the smart work.
Hard work is like 1+1+1+1+1 = 5.
Smart work is like 1*5 = 5.