There is another analogy here too. Why work a real job when you can go find something that you "love" to do and would continue doing even without compensation and STILL get paid for it.
Dream job right? Why not turn a "passion" into money?
The problem is that after the Nth engagement, it would certainly become a J-O-B like all else and would begin to lose it luster.
"You mean after having worked 10 hours already today and after having already serviced multiple passengers, I have to do another?...Am I refusing? Not really, its just that I am "fatigued" and would rather go home, honestly....What? I will be getting a call from the Chief P?....Fine...I'll do it."