These files are already compressed using formats like MP3, WAV, or MP4 variants. Compressing them a second time yields almost no size reduction.
If storage space or download bandwidth is your primary constraint, Steam offers built-in tools to help manage the size: Call Of Duty Black Ops 2 Highly Compressed 200mb
You can limit the download speed in Steam's settings so it runs quietly in the background over a few days without interrupting your daily internet usage. Summary: Is It Worth It? These files are already compressed using formats like