Hmmm... people probably should understand that pretty graphics == more power usage. Not that you can't optimize the power usage over time, but it's just a fact of life. You can see this in action in one way by checking out your CPU usage when playing a game... during the 3D rendering, processor usage is really high. If you pause it (and the game just shows a simple pause screen), you're using very little CPU power (probably little GPU too). Obviously, high CPU use means more power is being consumed (and you can feel your computer heat up).
So, yeah... if the game is rendering, it's using lots of power whether you're playing or not.
I'm actually happy to see an article like this. The author seems mainly to be suggesting that you just turn off the darn console when not playing it, which is a good idea both for power usage and for machine longevity... it just makes sense. I guess it's not something every console owner is aware of, though.