First AI will likely kill a lot of people at the behest of humans.
If I were a world power with a functional AI, I would immediately launch a full scale attack on foreign governments infrastructure so they couldn't develop a competing AI.
Why is AI better at killing humans than humans? What exactly is the threat introduced by "intelligence on silicon" rather than "intelligence on meat"? Why would an AI be better at attacking computers than humans using automated tools to do the same thing?
I've described to you the threat vector that people with high positions in the government are talking about.
An intelligent machine oriented towards 24/7 cyber attack with even parity human intellect is clearly a massive threat, let alone a data center full of them.