The difference between Reward Value and Eligible Product:
Reward Value: This is the product that you want to give as a reward (for example, the product the customer will receive for free).
Eligible Product: This is used when you want to create an offer like “Buy X product and get Y product for free.” The eligible product is the product the customer must purchase to qualify for the reward.
So in simple terms, Eligible Product = what the customer buys, and Reward Value = what the customer receives as the reward