That’s not what it says, at all.
Again—if you take this at face value:
“In the US, there is one automotive fatality every 86 million miles across all vehicles from all manufacturers. For Tesla, there is one fatality, including known pedestrian fatalities, every 320 million miles in vehicles equipped with Autopilot hardware. If you are driving a Tesla equipped with Autopilot hardware, you are 3.7 times less likely to be involved in a fatal accident.”
You can’t just throw out the unequivocal statement that it doesn’t stop accidents. If you mean “it doesn’t stop all accidents”, sure. Now, I get that the paragraph that I quoted above doesn’t make clear what the fatality rate is per mile of the autopilot feature being active (versus just “equipped with Autopilot hardware”), but I don’t see any basis for your statement in Tesla’s own release.
As it stands, I haven’t seen data supporting that it is the “worst of both worlds”. It may, or may not, be worse than your bog standard human, on average.