In terms of application, Bitcoin will find it difficult to replace all fiat currencies. Bitcoin is a financial innovation that has several advantages over the existing financial system.  It was not intended to completely replace fiat currency, but rather to give an alternative.

Bitcoin, like the Internet, is a revolutionary innovation that offers new ways of existence... however, while the Internet is widely recognized, not everyone in the world has access to it and is surviving.

So, don't let your fear of change lead you to assume that Bitcoin will reduce employment opportunities, because Bitcoin has generated and will continue to create many jobs.