It works brilliantly, 99.5% of the time. The issue is that the failure mode is catastrophic. Like getting confused with the lane marking and driving off the shoulder. And the complete inability to read construction zone signs (blasting through a 50 KM zone at 100 KM).
I'm deeply skeptical that the current sensor suite and hardware is going to have enough compute power to safely drive without supervision.
It will no doubt improve, but until Tesla steps up and assumes liability for any accident, it's just not "full self driving".
For me it looks like they will reach parity at about the same time, so camera only is not totally stupid. What's stupid is forcing robotaxi on the road before the technology is ready.
It's far from clear that the current HW4 + sensor suite will ever be sufficient for L4.