A specific but satisfying use case, my apt building was being stingy* with handing out RFID tokens so I used it to copy and program a cheap RFID token for lending to a trusted visitor.

* Stingy => security protocols that I agree with in sentiment but unfortunately I need to let my pet sitter in and it's nice to allow them to keep the keys as I travel frequently and key exchanges are less than optimal for my spouse and I