Highly unlikely. Digital currencies cannot function when the system is offline or communications are interrupted. Not long after bitcoin was invented, the first Bitcoin ATMs made it possible to convert bitcoin into hard cash or to buy bitcoin with cash. There is nothing mutually exclusive about the two types of currency, they can co-exist quite happily. In addition, there are billions of unbanked adults in the world as well as a huge digital divide between haves and have-nots. In that context, it would be unthinkable to deprive the majority of humanity of their access to currency.
Will digital currencies eventually replace physical currencies?