Bitcoin is, because we say it is. 

    I'll let you ponder on that for a moment.... Money as we know it today has already changed into a cryptocurrency, but is displayed to us as the dollar bill upon request. Electronic transfer or payments are all electronically moved and I'm retry sure it's not being transported in vehicles every single transaction that's made. So how is Bitcoin any different? That's the beauty of it, it's not. It's better. If you wish it presented to you in the flesh, it's possible but more difficult. Spends just the same though. If we rejected it and stayed with banks, they win. You lose. 

 The choice is yours.