I think this is meant to be a fun project that gets people to learn some of the quirks in the Javascript language. It reminds me a little bit of code obfuscation contests: the more deeply you understand the language, the better you will do. The advantage here is that it's not intentionally misleading and actually could be useful.

I agree... some of them are handy tricks that don't make the code obfuscated or less readable, but not all. Some people think code like this is clever or desirable, too. Also, I've actually seen code in jQuery plugins such as

    if(condition)
     //{ //save a byte!
       action();
     //} // save a byte!

as if leaving out the braces will actually make your code run faster, or make a real difference after minification. I could easily see that sort of person thinking this article is like an elite JavaScript style guide.