Earlier quoted context omitted.
Having the web page fade in slowly gives the impression of speed. It's not just a fancy gimmick.
I ran a website speed test on this page; it performed very poorly (load time more than 14 seconds). Personally, I'd rather see websites with real speed, rather than something pretty that just has the impression of speed. In my opinion, having a web page fade in is just a gimmick.
Automated website speed tests aren't a good measurement the way you're using them. They're good for a site developer to find bottlenecks but can't tell you much else one way or the other. Perhaps most of the page load time is spent loading images below the fold.
You're much better just loading the page by hand and seeing how fast the content shows up. And when you do that, the impression of speed is important.