People talk about Bitcoin one day becoming a global currency but something we don't consider is a currency is anything that you can trade goods and services for.
Money (Fiat or cryptocurrency) is only worth what people value it at.
Bitcoin is valued at ~330AUD$ and is used globally.
Bitcoin already is a global currency. It is used around the world and is technically valued higher than any other currency in the modern world.
It's arguable as to whether its a global currency. Sure, it can be used globally but in not many places. It would be very difficult to travel the world on bitcoin or survive solely on it. I hope one day this will change however and it will take time but I do believe it could become the worlds first global currency.
It's interest has been increased globally and will slowly become internationally accepted by almost all vendors. As for traveling, once you have enough money to trade with bitcoin you can become financially independent to spend on traveling and others leisure expenses too. Once the popularity increases every circumstance will support bitcoin.