Very good points and discussion here, did not know it would generate such reaction. i am the one who made it.
I was trying to explain to someone who is no-coiner the differences between bitcoin and current money and i ended up coming up with this.
1. in the short term, ofcouse fiat is going to co-exist with Bitcoin
2. in the long term, bitcoin could prove even more powerful as we are seeing in developing nations. many of them are using it as a means of cross boarder payments because of limiting payment gateways. it is not easy to move money in other countries as it is easier in Europe, USA.
3. fiat currencies are increasingly becoming digital but they are not crypto (censorship-free). they could even propel adoption of bitcoin since it will be easier to transfer from one form to another.
4. for most of developed nations, if it becomes adopted more, Bitcoin will act more as store of their wealth, it could change in the longer term.