That doesn't make any sense. Think about it. How does a cab driver get you to your location? Well you explicitly tell him by giving an address, or the name of a POI, or drop a pin on a map. You're then taken to the location you specified. Now, as you approach the location, you make a choice to either finish the ride, or abort it early by telling the driver, "Hey, this close enough. Just let me out wherever." At this point, the cab driver doesn't care, as long as he gets paid and you're happy it's a successful transaction.
So what does following you do? Well it finds your actual final destination. Which restaurant. Which house. Which apartment. Which store. So that brings up two questions. First, how does this true final destination information give a better rider experience? Well it's not exactly clear, since the rider gave explicit destination information at the start of the transaction, or explicitly ended the ride when they became satisfied. So, what's in it for the driver? Well that's not clear at all either, since rider was already satisfied and the driver got paid.
So what doesn't it do for Uber? Well, now they have popularity of specific POIs. Which bar. Which restaurant. Which store. That's valuable information. You could use that to deduce rider profiles that include things such as taste preferences, and income level. Then you can use that information for differential pricing (e.g. "This dude has a bunch of disposable income, charge him an extra two bucks.")
I'm sure there's other things you can do with it, but my point is that it's not useful for navigation, at all, but does give economic information which could be squeezed, and attempts to squeeze all the money they can from essentially a car service on demand app, is Uber's MO.