Error handling in command line applications is crucial for providing users with clear feedback when something goes wrong. Utilizing standard error (`stderr`) instead of standard output (`stdout`) for logging error messages is essential to maintain data integrity and assist in automation. While applications may print out results and errors to the console, mixing these outputs can lead to confusion, particularly when piping results to other processes or files. The use of the `log` package in Go simplifies error logging, as it automatically handles writing to `stderr` and includes useful features like exit status and timestamps. By distinguishing between normal output and error messages, developers can create more robust applications that inform users effectively without obscuring important diagnostic information.