It is said that bitcoin will destroy the fiat system but i believe that if this happens the world will change completly because banks and a lot of things will go out of market.
It is possible happen since nowadays, bitcoin is becoming more popular but it doesnt mean that if most of the people are now using bitcoin and other cryptocurrencies, it will totally destroy the fiat system. There will still be fiat money that will be use because not all people can use bitcoin.