They're within the story continuity. They're not going to contradict anything from TOS story wise. Visual wise, sure, but they're not going to kill off Kirk or anything.
I can only speak for myself, but the look is part of the story and more important than minutiae like the Eugenics Wars starting in 1992 or the 2161 being the birth of the Federation.
Plus, it'll be quite a trick not to contradict TOS as it contradicted itself sometimes.