"Crypto will replace the dollar", is the typical crypto guru pipe dream. Now I'm not saying this isn't impossible in the future, but let's be clear, it won't happen for a VERY long time. (However usage and implementation of crypto will continue to gain traction, recently even Starbucks has shown interest in this field in a duel effort with the blockchain startup Bakkt to make it easier for customers to buy their coffee/ other products with digital assets, (although not directly, but it's still a step forward). But anyway the main reason why Bitcoin or any other crypto can't beat the Dollar is simple.... Taxes. As much is anyone hates it or not, the government has the power to determine what you pay your taxes with. Currently your only allowed to pay them in USD, which means you'll always have to trade your crypto in for dollars at the end of year or face the wrath of the IRS. The power of the government creates an artificial demand for this otherwise worthless paper.
So until the government accepts an alternate payment method for taxes, you're stuck trading hours of work for toilet paper.