JSON Schema validation is a powerful tool in MongoDB that allows developers to define the structure and constraints of their data, ensuring data consistency and security. By using the uniqueItems keyword, developers can enforce uniqueness within arrays, preventing duplicate values and unauthorized extensions. This technique can be applied to various use cases, including validating array contents, ensuring data integrity, and preventing errors at a database level. The JSON schema validation process provides a flexible and scalable way to validate document shape and values, making it an essential tool for developers working with MongoDB.