Exam Certified Marketing Cloud Consultant topic 1 question 3 discussion

During discovery, the customer outlines data requirements and the anticipated use of Marketing Cloud with the following criteria:
✑ Customer data will be fully refreshed every night via Import File Activity from the customer's data warehouse.
✑ Contact records will be augmented by relational data tables via Contact Builder.
✑ Customer ID will be used as the unique identifier for each contact.
Which statement differentiates the use of data extensions over lists?