The parent's point was that, for driving, the "natural" human way is still better along one relevant dimension [1]: how much sensory data is required (SDCs need a lot more).
SDC engineers would regard it as an improvement if they could get SDCs to work using only the sensory data that a human would get. The parent was saying that Uber could show superiority by similarly doing more with less.
[1] Humans also drive with coarser control over the car i.e. no direct computer interface, just gripping the wheel and pushing the pedals.
Passive sensing lets your eyes see stars and comets: long range, power efficient, avoids sensor conflicts with other objects.
Imagine being able to see heat signatures at night, or through obstructions.
This is the kicker. Lidar allows companies to make up for a lot of the current shortcomings of state-of-the-art computer vision.
As to how easily Uber could advance state-of-the-art computer vision, CV is an academic field with decades of research efforts built up already. To be fair, CNNs are still young-ish in terms of producing results, but Google, FB, etc all have better teams than Uber in this area. The fact that every major self-driving car project except Tesla is using lidar says a lot about how insiders see the first-to-market strategy playing out. Relying on pure CV at this point is kneecapping yourself.