They will coexist with digital currencies for decades...but essentially the will be replaced by digital currenccies
I think this will be so far in the future. Digital currencies are so volatile that it changes it's price every single day. And who will be using that kind of money right? They will, for sure, use a digital currency in the future but I think it will be a day when digital currency is developed and ready to take it's path as a new currency.