And even with regards to the singularity or whatever, we know the thing is going to be dumb first. We were all dumb. Kids are cruel and irrational and love to play. If AI were anything like us, it'll be childish first before it surpasses its parents. No one seems to go there.
But the real threat is us wishing for daemons, not by accident, but on purpose. The open letter warns 'our AI systems must do what we want them to do.' As long as there are military interests, AI will be made into weapons first. Enlightened robotic butlers aren't going to kill us. Robotic soldiers will do it better, and do it first, and they will be obeying our orders.