Why? Where different editions exist, the reader will want to know which one they're getting, but they're unlikely to systematically prefer newer editions.
But also, Google Books isn't aimed at "readers". You're not supposed to read books through it. It's aimed at searchers. Searchers are even less likely to prefer newer editions.
That seems wrong to me. Generally when a new edition of something is put out it's (at least nominally) because they've made improvements.
("At least nominally" because it may happen that a publisher puts out different editions regularly simply because by doing so they can get people to keep buying them -- e.g., if some university course uses edition E of book B then students may feel that they have to get that specific edition, and the university may feel that they have to ask for the latest edition rather than an earlier one so that students can reliably get hold of it, so if the publisher puts out a new edition every year that's just different for the sake of being different then that may net them a lot of sales. But I don't think it's true for most books with multiple editions that later ones aren't systematically better than earlier ones.)
If Waymo has fewer accidents where a pedestrian is hit than humans do, Waymo is safer. Period.
A lot of people are conjecturing how safe a human is in certain complicated scenarios (pedestrian emerging from behind a bus, driver holds cup of coffee, the sun is in their eyes, blah blah blah). These scenarios are distractions from the actual facts.
Is Waymo statistically safer? (spoiler: yes)
Imagine that there are only 10 Waymo journeys per year, and every year one of them hits a child near an elementary school, while there are 1000000 non-Waymo journeys per year, and every year two of them hit children near elementary schools. In this scenario Waymo has half as many accidents but is clearly much more dangerous.
Here in the real world, obviously the figures aren't anywhere near so extreme, but it's still the case that the great majority of cars on the road are not Waymos, so after counting how many human drivers have had similar accidents you need to scale that figure in proportion to the ratio of human to Waymo car-miles.
(Also, you need to consider the severity of the accidents. That comparison probably favours Waymo; at any rate, they're arguing that it does in this case, that a human driver in the same situation would have hit the child at a much higher and hence more damaging speed.)