Chromebook's with Intel ULV CPU's , why ?

First was the Acer C7 and the Samsung 550 with a ULV pentium and then the chromebook Pixel with a i5 and now there are rumors of more chromebooks using Haswell CPU's on the way and i just ask my self why ?

ChromeOS is very light , why use more powerful CPU on it if it doesn't need it ? why loose on weight, dimensions, battery life and price?

Some claim is to pave the way to more powerful programs but it doesn't make sense . ChromeOS was created to be a very light weight and mainly cloud based OS , they had a lot of work to strip it down to a very light OS and now they are building it up again ? i don't get it...

What do you think ?