That's a bit of the problem with showcases, they tend to look like 90s flash animations, but that doesn't mean that the intention is recreating the exact same effect on regular web pages. But once you build a generic tool, showing off every feature isn't necessarily a bad idea, even if spuriously using it would be.

But generally I agree, animations are easily overused. They're quite useful for showing (and sometimes hiding) UI elements, as this leads to a interface devoid of shock and surprise. Heck, I think I read something about that in a paper that predates the web…