How is having recorded video of actual roads not valuable data? You're assuming the only option is training self driving cars on it. They might be training something totally separate to recognize signs, or see damaged roads, how quickly pedestrians react at different times of day, etc.
I agree that having detailed maps is an advantage. But they only make you a better driver in the places where they are correct. As such you can't rely on them to learn to drive, because you must be able to adapt to changes. Driving is not about the best case, but about the worst case.
Using uncalibrated and random positioned phone cameras to learn about driving a car that has better sensory equipment seems backwards to me. But point taken, the article says "learn more about driving overall." So that could be anything.
To reiterate, you cannot, ever drive based on any map, regardless of how many smartphones collected that map's data. You might use a map for navigation, but even then you'll have to deal with closed roads or changed traffic flow that isn't yet on the map. You cannot use maps for driving.
Well that's my sentiment too. But the article is wishy washy on the use of the collected data. Having local knowledge can make you a better driver after all.
Very narrow view point for you to take.