I'm OK being left behind, thanks!

Many years ago, someone tried to get me into cryptocurrencies. "They're the future of money!" they said. I replied saying that I'd rather wait until they were more useful, less volatile, easier to use, and utterly reliable. "You don't want to get left behind, do you?" They countered. That struck me as a bizarre sentiment. What is there to be left behind from? If BitCoin (or whatever) is going…