These are really sophisticated systems and they've really thought of a lot of issues. All of these companies have hundreds, if not thousands of engineers who have been working on this problem for over a decade, as well as an army of lawyers trying to get things into compliance. I don't think "well it can't do x as well as a human" is going to hold up in 10 or 20 years when these systems are clearly much safer. Human driven cars will eventually be uninsurable.
So do a lot of tech companies that make a lot of dangerous, fraudulant, or just bad products, or that try to develop technology that never comes to fruition.
The tech is impressive, but that doesn't lead to an assumption that it must be able to do whatever is needed. I've seen enough tech hype cycles to know them when I see them. In the end it will have great strengths and great weaknesses, and we should learn what they are.
But 'looking at gestures' isn't the same thing as having a real-time interpretation of the sensors. This, to the point of another comment above, may be conflating 'perception' with the larger problems of 'self-driving.'
Humans see a gesture and understand the meaning very fast because we process a lot of communication on the subconscious level. If you read the safety report of the Uber incident, it shows that the self-driving system could 'see' the pedestrian, but it struggled to effectively classify them. To be fair, that was years ago and another company, but we (as the public) don't have much insight into how good (or bad) the software is.
So 'seeing gestures,' 'correctly classifying gestures', and 'correctly classifying gestures in a time-sensitive manner' are varying levels of difficulty. The last one is the one that matters for safety-critical operations, and the requirements change with the velocity of the vehicle. IMO, there should be a regulatory framework that addresses a baseline of performance on these systems.
But can they look at a driver's face and realise that they are distracted with their phone and haven't seen you?