Used to compress your JS code online, it has an option "Include latest jquery.min.js", which is very useful for improving speed.
Reason for recommendation: Minify the code = smaller file size = faster web page loading speed
Used to convert the compressed code back to its normal state to make the code readable again. This tool can also be used on obfuscated code.
Recommendation reason: Beautiful code = easy to read = faster development
Used to protect (obfuscate) your code and make it unreadable. Obviously some imitators can use a tool to deobfuscate/decompress, but the more protection you can put in place for your code, the better.
Recommendation reason: Obfuscated code = unreadable = protect the fruits of labor