Useful for minifying your js code online, also there is an option to include the latest version of jQuery.min which is pretty useful for speed.
Why use? Minified code = Smaller filesize = faster website loading times.
Useful for converting minified code back into it’s normal “pretty” form (ie making it readable again). It also works for obfuscated/packed code which is useful.
Why use? Pretty code = easier to read = faster developments.
Useful for protecting your code against quick sight of code, by making it unreadable. Obviously the keen copycat can use a tool to deobfuscate/unpack the code but the more deterrents the better.
Why use? Obfuscated code = unreadable = harder for someone to copy code