I don't think that's what the economist is saying. If you don't know that they were at the same time, then it could just be that low phone batteries and high Uber prices both correlate with it being later in the night. They're not saying that Uber is guessing the time you call for a cab based on your battery percentage. Obviously Uber knows when you're trying to get a ride because you contacted Uber to get one at a specific time anyway.

these things are often not driven by hand made or even understandable algorithms but by linear algebra and it is possible for a model to make that kind of connection even if there is a better indicator. idk what ubers pricing algorithm looks like but if it is a neural network which is used to determine what people are willing to pay for a ride then it could have a preference for higher prices at night and also its more likely for people to have low battery at night so it also has a weaker connection between low battery and high prices.