Waymos crash less than human drivers

Serious crash rates are a hockey stick pattern. 20% of the drivers cause 80% of the crashes, to a rough approximation. For the worst 20% of drivers, the Waymo is almost certainly better already.

Honestly, at this point I am more interested in whether they can operate their service profitably and affordably, because they are clearly nailing the technical side.

For example data from a 100 driver study, see table 2.11, p. 29. https://rosap.ntl.bts.gov/view/dot/37370 Roughly the same number of drivers had 0 or 1 near-crashes as had 13-50+. One of the drivers had 56 near crashes and 4 actual crashes in less than 20K miles! So the average isn't that helpful here.

Is Waymo doing ‘easier’ miles than an average human in any way? How limited is their range and types of roads they’ll use?

Yes, vastly easier.

As I understand it, they limit their range to a few cities in the American Southwest and West Coast, and don't operate in bad weather.