Why do stored procedures and functions improve performance?

Stored procedures and functions improve performance primarily by reducing the amount of data sent between the application and the database server, as they allow for complex operations to be executed within the database itself. They also enhance execution speed since they are precompiled and stored in the database, leading to optimized execution plans. Additionally, using stored procedures can minimize network traffic and improve security by encapsulating business logic within the database. Overall, these factors contribute to more efficient resource usage and faster response times.