If you have 10 bank notes in your wallet, you have 162,285 times as much plastic in your house.
I think most people would have had used some basic common sense that even their trash bags are many times more plastic than the polymer bank notes they use.
Why did you possibly think that anyone should be focused on microplastics from bank notes?
At what point do you go from "just asking questions" to "maybe this is a bizarre thing to focus on" ?