What are the chances of living in a world with no actual money ? 
Low. I think personally that cryptocurrencies wont make FIAT useless, but I think that cryptocurrencies will work hand-in-hand with FIAT money. Especially in countries like the United States, and the other first-world countries; I don't see FIAT going anywhere soon.
I agree with this guy is saying. Fiat and digital currency could work along together, but in cases where our world is beginning its era to s modern and more computerized and hitech, I bet digital currencies will have its weigh more on the top.