Because i'm totally broke and can't afford the setup at the moment. Got an LG1+ sitting in the garage for when I can though. Plus all ourt XC tracks here are flat, so SS is fine. And it saves weight, went for a weight conscious build when I picked the parts, CK headset, Mag pedals, air both ends etc etc.
Same headangle as my blindside 66 degrees, if the 1 degree per 20mm of fork travel extra is correct. Normally a 68 degree headangle with a 120mm fork, so should be 66.