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.
The president could not order that bitcoin (or any other asset) be confiscated. This would be against both the 4th and 5th amendments to the constitution. Although for president Obama, this does not seem to matter.
You also very much have counter-party risk when dealing with bitcoin. If I were to purchase a widget from you and I send you bitcoin I would be risking that you would not send me the widget that I paid for or that the widget is somehow effective, or that you somehow try to steal the widget back from me.