Why isn't in's Creed used as a benchmark test while reviewing graphic cards ?

in's Creed isnt that hard to run. I can run it with my ATI HD 4850 completely maxed out at 1680x1050. While it does take a mid to high range graphics card to run it well, it isnt hard enough to run to differentiate between the high end cards' performances (4800s and GTX 200s). Crysis and GTA IV are still much harder to run.