Travel to other countries without a visa? If so, how will the government recognize people from other countries and how do they know if he is clean from illegal activities?
But if you mean that we can pay using bitcoin rather than fiat/credit/debit/other payment, maybe we will see it in the future, which is our benefit because we already have bitcoin. But you can still dream like that and wait for when that happens but I guess it is hard to see yourself traveling to other countries without a visa. Maybe there will be another method to check every citizen from all countries.
Still ability with some countries for traveler make their journey without visa because between traveler or tourist and destination country have bilateral relationship, but when bitcoin adapting as legal currency transaction will make easy for traveler because they don't need exchange cash or their cash or fiat money.
Just spent or pay by using bitcoin for all transaction from ticketing, hotel or all payment need by traveler, will be easy without exchange if bitcoin have been legal currency transaction. Nice dream when bitcoin have been support on many side and we don't need to bring cash money or fiat for every country destination exactly for ever traveler want to make journey around the world.