It's not a matter of performance gain. I agree with you on that issue: It would be the relatively rare page where it would make a noticeable difference.
I like Felgall's style because:
(1) It introduces NO global variables into the page, so you can't possibly conflict with any other scripts on the page.
(2) It almost always needs less total code to implement.
I wasn't sure I liked the style, at first, but I have swung completely around to Felgall's way of thinking. In almost all new coding I do I use that style.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.