How would this work though? You’re not ordering your food via the QR code link, you’re telling the waitstaff. Unless they ask you what price your saw, how are they going to correlate their variable price to a particular customer?
However, this would make it a lot easier to implement “peak pricing”. Their menu could automatically update based on time of day, or day of week, and certainly holidays.
https://www.nytimes.com/2021/05/16/business/bill-melinda-gates-divorce-epstein.html