If something is enjoyable and rewarding, like making art or an invention, I'd want to do it myself. If a job is unenjoyable and unrewarding, I will use the fruits of my labors to get someone else to do it. I will pay a lot of money to whoever cleans my septic tank. Does that make septic tank cleaners socially valuable, or does that make having a clean septic tank valuable? If a machine can clean the septic tank and no one has to do that task anymore, then I can get what I want without either having to toil myself or convincing someone else to toil.