I think Mark has addressed this before, and says that they are primal approved, but IN MODERATION. There are some recipes he uses with the nuts as well, so I wouldn't worry about it. I eat them myself occasionally. He does highly recommend macadamia nuts though, which I myself find to be the most addicting primal snack in the world!
Overall, I'd say enjoy them every once in a while - besides, they are a powerhouse of other nutrients