Pros: 1. It's a new addition, personally I always approve of more features to the game. They keep the game fresh and may add up to fun sometimes. 2. Rewarding for smaller cities. EDIT: 3. It doesn't feel like a must-do, and that's a good thing, since most other quest chain events feel too valuable to miss out on due to decent culture building rewards. Cons: 1. Not rewarding enough for big cities, thus, these people may not be motivated enough to get out of their skin to reach the final prize, and rather just stick to their normal daily routine.(EDIT: Spell fragments and catalysts are rewards I wouldn't shy away from, it's an OK reward that you get without interrupting your gameplay) 2. This one may be minor, but, I don't think word "challenge" fits the name of this activity. Call it labor, rather. Craftsmen' Labors.