The unique combination of benefits that users receive from 3M's Flag Highlighter, such as durability and convenience, is known as?

Customer value.

Explanation:

Customer value is associated with the kind of gratification or value that a customer gains or experiences after communicating with a firm or company for purchase or sale of a product or service.

As per the question, the distinct combination of advantages that the users receive from 3M's flag highlighter like durability and convenience exemplify 'customer value' (gratification) that the users/customers experience in return for the amount they pay for the service from the company. Therefore, 'customer value' is the answer.