I'm somewhat surprised. I had bought into the "all machine-learning is done on-device" messaging and thought that Apple Maps was taking pains to anonymize data by only sending small chunks of your route data for traffic congestion analysis/etc.

When Apple was starting their machine learning division I'd heard they had trouble retaining top talent because the engineers would show up and "okay! where's the data?" and Apple would reply "uhh, we don't have any it all stays on-device".

But with Apple getting into advertising I don't think this could stay this way, if it ever actually was in the first place.