I just assumed it was because people would rather pay $20 and be told that they saved $3.26 on their $23.26 bill than be told that their bill came out to $20.

I just assumed it was because people would rather pay $20 and be told that they saved $3.26 on their $23.26 bill than be told that their bill came out to $20. I'm really not sure what information I'm giving up by scanning a barcode on a card that the store gave me. Obviously they can use that to record my purchasing history, but they can do that anyway through a myriad of other techniques.