Could it be possible that in the future there are countries that use bitcoin as the national currency??
Not so sure that any country would use bitcoin as their national currency, but we can think or consider that bitcoin can be used as a center of all other currencies of other nations like it is used now in trading. Sure it can be the most used currency but not the national currency. After all you dont possess bitcoin physically. People would prefer something they can touch or possess as their national currency.