> Individual users' data is very closely guarded internally. It's immensely difficult to look at user data without specific access. Overwhelmingly, this data is queried in aggregate and fed into machine learning systems. The risk of abuse is exceptionally low.

For now. You haven't mentioned how long this data is kept, which means I can assume "forever". This means that a future change of policy, an acquisition, or a merger can expose this data to a variety of third parties (not to mention the obvious possible exposure to governments).

The reasons you have listed for gathering the data are not sufficient to offset the future risk to me. Moreover why should I do unpaid data acquisition for Uber while bearing all the risk in case the data is exposed? If you want higher detail location information, do what Google did and send out cars with sensors.