iOS 6 metallic button bling is both unnecessary and awesome
It is one of those small things that you probably wouldn't notice for a while if someone didn't point it out, but adds a pretty cool effect when you do notice it. Of course, it's also one of those details that makes you wonder if Apple couldn't have spent its time a bit better and instead of adding this effect, maybe the team could have been working on something like a widget system, or sound profiles. It's also a detail that happens to remind us that background processes in iOS are given a lower priority than UI processes. So, if you're downloading something in the background, the speed might drop just a tad when you tilt your phone, because the metallic buttons have to change reflection.
Still, it does look pretty cool, and that is the whole point, right?