Say you have a BOGO Drink reward. As a business you understand that when this reward is used, a customer typically spends $20 because they purchase another two drinks plus an appetizer (~2 Draft Beers = $8, 1 Appetizer = $12) before they close out. You'd set the Action Value to $20.00, and since 4 customers have already used it, it's generated $80 in total Reward Value.
Another example, say you offer a Free Range Bucket reward. You know that when a customer comes in to redeem it, they typically spend $20 because they purchase a drink (~ $5) and a medium bucket (~$12). You'd set the Action Value to $17.00. If 10 customers redeem it, your total Reward Value would show $170.00.
Another example, say you offer a spend $50 on golf shop merch get $5 off. You know that when a customer comes in to redeem it, they are going to spend at least $50. You'd set the Action Value to $45.00 or higher if you know they typically spend more when they get this type of reward. If 10 customers redeem it, your total Reward Value would show $450.00.