But regardless, investing in bitcoin is a bet that people worldwide are going to need a decentralized currency with a solid monetary policy. We don't invest in bitcoin just because of the fact that everything is moving digital (I mean, PayPal and online banking are already digital for a while).
I would say not only decentralized but also anonymous if used well. Paper money can be replaced by digital means of payment, as it is happening, cards, payment by mobile or smartwatch.... The point is that digital payments mean a loss of privacy. Your bank, and the central bank of the day will know everything you spend your money on. With Bitcoin used in an astute way and maybe with other cryptos, we will be able to maintain privacy.