Digitalization is where we are all headed and even if we might not get to live until the day where everything is digital, I think it is inevitable. The changing needs of man have turned in a lot of new discoveries. Bitcoin and other digital currencies might not be necessary now, but in the future, today's wants might be tomorrow's needs. And if you can accumulate as much bitcoin right now, good for you and the next generations that will come after you.
Why just bitcoin? After watching a movie
https://bitcointalksearch.org/topic/m.21153900 I understand how much important is diversity. There can`t be one man in all world, and just one plant, nothing is one and one can`t do much alone. Current monetary system is made rich people to be richer, virtual currencies gives back the power to individuals and groups outside that system.
Like nature have different ecosystems thats what kind of economy we should have around the world, and with crypto currencies now its possible all people to be connected. Every town and village can have their own altcoin and work for it or use it, but in any time you will be able to buy what ever you wish with your altcoin or exchange it for other crypto.