It is said that bitcoin will destroy the fiat system but i believe that if this happens the world will change completly because banks and a lot of things will go out of market.
Bitcoin will do more to 'strengthen' the fiat system than destroy it.
Look at Bitcoin as an upgrade to the fiat system. A patch if you will. Much like how cash was an upgrade to the IOU system created by goldsmiths.... Just like how another upgrade, bank orders and cheques, were introduced by banks who would rather their customers did not pull depositsfrom their own vaults, but instead issued paper IOU's that would be cashed at other banks. And then credit cards were introduced to bolster the debt based economic system of today.... Now Bitcoin.
Cash was a very important upgrade for the fiat system, and the Internet is calling for similar technology because credit cards have failed. Hence, Bitcoin.
Bitcoin is not really a currency, it's a digital ledger. With inputs and outputs.... A private key grants you access to 'one line' in this digital ledger. And the whole point of this system, is to allow users to move value around the internet - without having to part with personal information. i.e Cash.... Digital cash... "Digital currency"
In the future a debt based mechanism will arise to be used in tandem with Bitcoin.
This always happens whenever an upgrade is made to the transactional side of an economic system.