15 years? I think even in 30 years we will still be using paper. First Bitcoin has to become stronger and more stable.
15 years is already enough to see that there will be half of the total population of the world will be using bitcoin, crypto currencies and for sure digital currencies or will make transactions automated. I had to believe with it because the world government will have their own currency and will implement the usage of it.
Guys be realistic please, bitcoin is just a digital thing. It can't replace dollar, soon or lately. Dollar will maintain to dominate world economy. And nothing can avoid this.