It does make sense when you look at it from an OEM standpoint. Lets say DELL or HP is offering you a pc with integrated graphics, they give you the option to customize with either the 2600 or 2600k and tell you that your Graphics performance will be best with the 2600k.
As said before most people do not overclock. And it does say the K series GPU can be overclocked on the H67 chipset.
Edited by Neur0mancer - 1/19/11 at 8:48am