The best-selling financial book writer "Rich Dad, Poor Dad" said Bitcoin would replace the US dollar, which he called "counterfeit money." In the April Sane Crypto podcast, author Robert Kiyosaki said the practice of printing more money in America was to create bubbles that would explode. "I think the dollar is toast because gold and silver and cyber currencies will take it," he said. "The US dollar is a fraud. I think we are watching the end of the dollar. "
https://www.youtube.com/watch?v=unvFvAUCZEUCryptocurrencies is a form digital money like credit card and people are likely enjoying in using credit card so maybe this will overtake Fiat money.