Acharya Prashant explains that the common distinction between hard work and smart work is a false choice, comparing it to choosing between the devil and the deep blue sea. He defines hard work as doing something without knowing the purpose or the self, driven only by the instruction that doing is important. Smart work, often associated with cunningness or shortcuts, is merely an efficient way of doing the same mindless tasks. While hard work eventually leads to physical exhaustion, smart work allows for continuous, mindless activity through efficient machines and methods, preventing true relaxation.