Many of the same people who buy the Bitcoin-as-global-reserve-currency scenario also believe the Euro is going to collapse. It has known problems as a monetary union without a fiscal union, which lead to periodic bailout crises.

Here "deutsche mark" (and lira, which is another dead currency) are stand-ins for whatever national currency emerges after a Euro collapse. It may not be called that, but the point is that there will be some German national currency that settles up into Bitcoin in the international markets.