I can see the potential benefits, Danubius, but I'm concerned it might overcomplicate the experience, especially for seasoned collectors like myself. Most of us already have around 90-95% of the banknotes we receive, so this system might force us to either list all the banknotes we receive (making the task to satisfy our preferences unbearable to others) or unfairly discriminate against certain ones, like Indian banknotes. This could create a negative impression and might not be as effective since users can still choose to send Indian banknotes they prefer, potentially leading to the same issues. So, I'd keep it simple!