There are things which you will probably never be able to do in any cybercurrency, such as pay your taxes, tip your waitress, rent a car, buy airline tickets, buy or sell titlable property (real estate, vehicles, etc.) These transactions require either physical cash or credit cards, or must be denominated in national currency for tax reasons.
Also, a national currency is backed not only by the faith of the issuing government, but by its judicial authority (to enforce contracts, etc.) Bitcoin by its nature is not backed by any judicial authority; so if a dispute arises concerning a contract denominated in Bitcoin, will any court agree to enforce it? I rather doubt it. Thus, few will want to receive their wages or bid for a contract job in Bitcoin.
I see Bitcoin's role as an adjunct to national currency. Only in highly abnormal circumstances (such as the complete collapse of a national currency) could I see it acting as anything like a substitute--and then only temporarily.
I would agree with every point, if we are only comparing Bitcoins to traditional currencies. But most greatest thing about Bitcoin is that it is new phenomenon, it brings new ideas and probably will be game changer.