there are two other salient differences between hard work and long work - hard work when the person is skillful enough to do it is energizing, long work is always draining.
If by 'energizing' you mean morale-boosting, yes. But hard work is generally taxing. You are paying for long-term happiness with short term pain. Having slain a dragon on Thursday, you are likely to be in high spirits on Tuesday. But for the rest of the day and possibly tomorrow, you're may be sitting here doing menial tasks or reading documentation.