We know how to make fast robots, we know how to make safe robots, and we know how to make useful robots. But we do not know how to make fast, safe, useful robot

We know how to make fast robots, we know how to make safe robots, and we know how to make useful robots. But we do not know how to make fast, safe, useful robots. A faster robot would need to be heavier to do the same work. Any robot that can move as fast as a human and perform similar work to a human will need to be close to as strong/heavy as a human. And humans can kill each other with their bare hands; we just know not to. A Kuka LBR iiwa can only lift 7-14kg, but could easily accidentally kill/maim someone with common payloads of that mass. Obviously there's also some slowness w.r.t. the actual control here (i.e. safety pauses, planning latency, etc.), but it's a tall order to build any kind of home robot - especially one that has such a large workspace - that is intelligent enough to be both fast and safe.