Evaluate the effectiveness of different ad set-level lever strategies in the following scenarios. Identify which ones are using ad set-level levers effectively to improve ROI:
- Scenario I: A beauty products campaign uses detailed audience segmentation, targeting users based on their past purchase history and interactions with the brand.
- Scenario II: An electronics retailer allocates equal budgets across all ad sets, regardless of their individual performance or audience engagement levels.
- Scenario III: A travel agency employs a manual bidding strategy for ad sets targeting seasoned travelers, leveraging the team's deep understanding of this customer segment's behavior.