Read the next sentence: "We only care about machines insofar as it serves us."
Imagine a machine doing "work" that only serves itself and other machines that does no service to humanity. It would have no economic value. In fact the whole concept of "work" only makes sense if it is assigned economic value by humans.
Then we agree, but your chess example made it sound like if a machine could automatically pack meat with little human intervention, people wouldn't want it. That's also not the next sentence. How is it broadly applicable to work?
Imagine a machine doing "work" that only serves itself and other machines that does no service to humanity. It would have no economic value. In fact the whole concept of "work" only makes sense if it is assigned economic value by humans.