[yourenotsmart]

Hmm, someone downvoted you for asking a good question, for shame, Hacker News.

A printed QR code adds few complications to the process:

- You can't print the QR code with the rest of the cup, as it has to be unique. So we need a separate printing step. That also adds costs, and the question is does it cost almost the same as embedding an RFID chip (which is 7-10 cents).

- You need to align and scan the code before a refill, which is a lot more intentional for a customer, than simply holding the cup for a refill as usual. So it's worse customer experience.

- The only flat surface of the cup is on the bottom, so any spill means you're spilling drinks over the scanner. So that would mean scanners constantly requiring maintenance to keep working.