I think the video of the "car" moving around the paper map shows a lot of the value. You can rapidly prototype UI elements, experiment with camera angles/motion, etc. Amsterdam's streets in particular would have numerous difficult features (sharp turns, driving under bridges, tunnels, etc.) that would make it ideal for solving edge cases.

Full disclosure: I work at Uber, but not on this team, and have no insights into their process outside of this blog post.