It can destroy us if we entrust it with too much stuff. Let it run all the stores, and the logistics for those stores. And military logistics while we are at it. Maybe balance our power grid. Let it suggest governmental policy. Teach our kids.
It won't destroy us because it "decides" to; LLMs do not make decisions. It optimizes for certain goals, using shitty instructions and shitty training data. Which means that under certain conditions it can make completely unexpected and illogical actions, like those Chinese bipedal robots glitching out. So... it will destroy us because - under certain conditions - it will utterly suck at its job.