As we all know that bitcoin now are being made as a trading pairs to different fiat money all over the world. And we you go round the world having a good vacation on different countries you do not need to bring more fiat or physical money instead bringing gadgets and connecting to internet is enough to get fiat money after it will be traded to local exchange. In this way there is no need for one to bring more physical money as bitcoin could unify all fiat money around the world as trading pairs.
That right, Bitcoin does't only have huge potential, but it also can unified currency over the world as you mentioned the reason. However, we need a bitcoin Bank in that case, because we can not withdraw our money anywhere. It is not enough just bringing a gadgets or others devices and connecting to internet. We still need an authority where we can withdraw or money when we go to other countries.