[ars]

It costs resources simply to make the device. They tend to cost much more than the simple bricks, which means they use more resources than the simple bricks.

And unlike the bricks which you have approx 1 per device, with outlets you need too many of them.

[icebraining]

I don't agree that being costlier means they use more resources, but no argument about needing more chargers this way.

On the other hand, you could buy a single beefy converter (something that could manage a few amps) and then pass 5V DC cable along the regular AC wiring. Not sure about the efficiency of that, though.