MongoDB's Tag-Aware Sharding feature allows for flexible and efficient data management by enabling the creation of policies that affect where documents are stored based on user-defined tags and tag ranges. This feature can be used to maximize performance, optimize storage, and implement data center-awareness in applications. Key use cases include optimizing physical resources by moving infrequently accessed data to cost-effective archive storage, separating data by location for global users, balancing unsharded collections across a sharded cluster to distribute read and write load, and targeting specific servers with heavy indexes to reduce contention for limited physical resources.