In portable computing, it can help battery last longer. Just because it is not user facing, does not mean it should be ignored by engineers.
As soon as microsoft tries to release an IEbook to compete with the Chomebook, this metric will have a greater impact on battery life.
Yes, but the article specifically states that the efficiency is gained by by better utilization of PC hardware. I suppose if you're using your laptop exclusively for browsing it might make a difference, but switching to a tablet would give you even more battery efficiency.