I think it's just because first, entertainment is an example anyone can relate to, and second, he's a game developer, so entertainment is the context he is work

I think it's just because first, entertainment is an example anyone can relate to, and second, he's a game developer, so entertainment is the context he is working in. And look, less than half way in: "... The same metric can and should be applied to all activities: is the experience worth the irreplaceable hours of your life? Not just consuming media, but hobbies, travel, acts of creation and destruction ..." Anyway :)