yes currently there is nothing wrong to paper money, because still almost all the people of the world using fiat currency, but as soon as the trend of online currency is increasing the value of fiat currency is decrease, and a time can come when all the people of the world will be using online currency.
Time will surely clear everything. Though we feel that the world will turn its face towards digital currencies and fiat will disappear but still somewhere in the mind it keeps poping up that there will still be people willing to use fiat even after a revolution of digital currency in the world.
Paper money will disappear one day. But that will happen not too soon at all. Bitcoin is just in the beginning of it's history and it's rising, not just by the price, but as currency. The problem of today is that not every human can understand bitcoin. And many people think bitcoin is a new pyramid. But time will place everything on it's place soon.