maybe in the future paper money will disappear, but i think it will takes very long long long time. the reason is simple, in order to replace paper money you must do it all around the world. and for example country A and country B have different economical condition, advance in technology, the way of thinking of the citizen, etc that will takes a long time to adapting with cryptocurency. in the present time, we cant denied that there are a lot of people that is didnt know and didnt want to know about cryptocurency(advance currency in financial sector). so i think it will takes very long time, maybe in next century or maybe in next several decade