As I mentioned in another comment, some friends of mine worked at a startup that's entirely built around receipt scanning and itemization, and your comment alig

As I mentioned in another comment, some friends of mine worked at a startup that's entirely built around receipt scanning and itemization, and your comment aligns with what I heard from them ad nauseam: receipts are hard, in large part because there's just no standard way of putting things onto them. How do you show subtotals, taxes, and totals? How do you flag that an item is taxable or not? What's part of the header? What format are the numbers? What kind of subtle background text is on the receipt? Is the receipt at an angle? Is the picture taken of just a receipt, or a receipt held up in the air, with stuff behind it? Sometimes, there are lines on receipts that are just meant to be ignored, maybe for old tax regulations that don't exist anymore but were important when the receipt-printing software was written. It's a mess.