Human beings visual systems are far faster than once per second. Your reference is complete reaction time to both process visual information and decide on an appropriate action and actuate a control surface given a state model of the world. Your brain most certainly processes visual information faster than 17 fps doing novel segmentation and odometry.
Tesla's system is also doing much more than simple segmentation and visual odometry. Tesla's latency around actuating the control surface is quite insignificant (a few ms) so I'd argue it is a fair comparison.
In the "FSD Preview" update that came out around Christmas time, the car now shows a bunch of symbols on the road, and signs (aka stop signs) that it recognizes. They don't flicker at all, even while you're driving and a large truck obscures the car's vision of the sign / stoplight. So they likely have started to enable some form of temporal memory into the system so that it remembers what it has observed in the environment both frame-to-frame and overall.
That hasn't been my experience. The visualization only ever shows what I can see with my own eyes, and the cameras are in a very similar position. I've definitely watched traffic signals come and go, all while not moving an inch.
Really doesn't matter how fast it is if it doesn't work does it? Don't let all the impressive CNN results fool you, we are a long, long way from doing human level vision.
These videos are quite old. The current system runs at 60 fps on all cameras. The old system was limited to a single camera at 17 fps because of the hardware processing requirements.