- No central bank to limit what you can and can't do with it.
- No external countries/large companies/speculative investors devaluating the value of your savings through their own agendas.
- Easier international travel.
- The value of the currency can be determined by what people are willing to pay for products. Therefore it has no intrinsic value like gold or oil which would allow one entity to monopolize it.
- Some countries have currencies that are very weak. Generally this is not the fault of the people living there but due to historical or political reasons. A large international currency will give the citizens of these countries the opportunity to trade in other markets and at least a small amount of security.
There would be disadvantages as well though:
- No regulatory protection. One large company can horde all of it making the rest of the world poor. In a way this is even worse than international market manipulation as we know it. On the flip side, because everyone is using the same currency there is no clear beneficiary nation.
- How do you define it? Can it be hacked? Will advances in computing wipe it out? Who will print it?
For these reasons I think that Bitcoin had something. It is unfortunate (or fortunate?) that it did not go mainstream. Or, if we had an international currency, what it the next step? A world government?