Well that should help make your page load faster and so is worth doing.
The point I was trying to make is that minifying all your scripts is worthwhile. Trying to compress them using Packer or similar is not worthwhile because while doing that can make the file slightly smaller it means that there code that needs to run after the page has been downloaded to unpack the script back into code that can actually run.
Since most browsers and servers now support the downloading of gzipped versions of the files the actual amount of data to be sent from the server to the browser will be less than the original file size. So your minified js file may only actually need to send 8k to the browser in order to download the 13k script whereas if you used Packer the 20k script might compress down to 10k which then gzips to 9k to send to the browser and then still needs to beunpacked before it can be run (all file sizes are estimates and would vary depending on the actual content of the script but this should give you the general idea).