More diverse, higher-quality goods become possible due to labor focus (I only hunt, so i get great at hunting, you only farm, so you get great at farming; we end up with excellent meat and excellent vegetables.) alternative: you can only consume what you create, like Robinson Crusoe, and your time and attention are scarce
You likely also need a market in order to properly trade your specialized goods.
variation-between-individuals-is-required-for-societal-success