That gave me another idea which I haven't considered the implications of, but it sounds fun and video game'y:

Electronic/Smart bills, that keep track of how many times they've been used to purchase stuff with.

After a bill has been circulated N times, it increases in value by Y, and/or unlocks special artwork.

Some bills may become highly sought-after collectibles worth far more than their face value.

Would it help or harm the economy?

Well that shifts the value away from the bill being a promissory note and back to being the actually valuable item. Kind of like a commodities backed currency, which most nation's try to avoid.

The amazing thing about currency being actual valuable things (like precious metals or gems) is that it cannot be devalued by "printing" more of it from non-valuable things.

Nations try to avoid this because they can spend freely on a promissory note currency system. It is a recipe for disaster in the long term.

The difference being that the fed can actually reliably keep that promise, since they can issue new currency and borrow at extremely low rates...

Edit: https://money.stackexchange.com/questions/5400/why-is-the-fr...

I'm being a bit hyperbolic, but only a bit.