Things are not as far away as one might think. A single penny is worth only 110 satoshi right now. And with bitcoin rising, that satoshi-to-penny ratio is dropping. Maybe somebody with better math skills can figure out what one penny was worth in satoshi a year ago...must have been a few hundred satoshi to one penny. It's happening.
Traditions will be needed when the Satoshi Day comes. Fireworks? Songs? Lighting your favorite fiat bill on fire and launching it with one of those Chinese lantern things?
You are 100% correct. The BTC will be the future currency surely.