"Apple also says that it’ll use machine learning and Apple Maps to label stores that you use in the app, and use that data to track purchases across categories like “food and drink” or “shopping.”"
"Like many of Apple’s products, privacy is a big push here. “Apple doesn’t know what you bought, where you bought it, and how much you paid for it,” said Jennifer Bailey, VP of Apple Pay. All of the spending tracking and other information is stored directly on the device, not Apple’s servers. The company also promises that “Goldman Sachs will never sell your data to third parties for marketing and advertising.”"