I would suggest OP to watch this documentary which explains many things about your question.
The movie is called 'Bitcoin The End of Money as We Know It' watched it today and it's impressive.
Bitcoin can not replace dollar but bicoin will be one day the first e-currency being used online.
I agree. This movie really opened my mind. It really gives you insight on how fiat works, who controls it, and why bitcoin makes sense. This movie should be a prerequisite in schools.