It thinks the south bay is a desert, my house has a flat roof and windows instead of a garage, and so do all of my neighbors. Not a bad theme, but not very accurate to present day. Still impressive.
If you zoom out enough, it goes back to OSM, so I wonder if it's doing a tile by tile conversion, but I wonder how it could be sped up.
You can help improve accuracy by contributing! It's not that hard and some editors are very easy to get started with, e.g. https://github.com/streetcomplete/StreetComplete (If you're on Android).