Concurrency in Go enhances the efficiency of data processing, allowing developers to tackle issues like file reading without multiple passes over the data. The lesson focuses on optimizing a counter function that previously required resetting the file read offset multiple times to count words, lines, and bytes. By employing a single-pass algorithm, the lesson demonstrates how to utilize the `io.TReader` function to create a reader that reads from a file while simultaneously writing to another buffer. This design enables concurrent operations to gather counts without the redundancy of loading data into memory repeatedly. The session emphasizes the importance of memory efficiency and introduces the use of specialized types to further improve performance, paving the way for even greater optimizations in future lessons.