There are a few other factors that make Bitcoin ideal:
-Bitcoin has no counter party risk: no one can devalue them
-Bitcoin can't be confisicated. Unlike gold in 1933:http://en.wikipedia.org/wiki/Executive_Order_6102
-Bitcoin can be sent over the Internet.
The president could issue a similar order regarding bitcoins, it would just be impossible to execute.
It is not much different from gold confiscation. Except today much harder to even consider such action like gold confiscation to be possible.