1) Assigning some fixed dollar amount to coins for the purpose of demonstrations in the article. This will never happen, it's in flux, and it's a scarce resource. Does gold or any other precious metal stay at a fixed resource, does anyone hoarding gold make it any less valuable?
2) As mentioned above, bitcoins can be traded in almost any fraction thereof, simply having each coin be worth 2 million dollars, is irrelevant.
3) If too many people start hoarding and there is no exchange of coin, it is possible that the value of coins will decrease instead of increasing. Please remember that the only value assigned to the coins will be the value that individuals are willing to assign to it, or pay to acquire it, or amount of coins willing to exchange for goods or services.
4) We've had commodity backed currencies for much, much more of recorded history than we've had fiat currencies and yet we've brought civilization to where it is today. Can we please stop assuming that any commodity backed currency is destined to be a failure because we currently favor a currencies that are by definition even more worthless than Bitcoin?