Because it's unusable. And it's awesome only because pretty few people hack their own portfolio into an unusable format. If more people did it, even if the format was different for each (which is hard to imagine), the cool factor would be overshadowed by the frustration and impatience these elicit.

Now since very few people do it (or at least it's definitely new for me), it does look cool. But I'm also happy that I didn't have to read through the whole thing and I could stop after a few minutes of scrolling.