Bitcoin was originally created as an alternative, decentralized payment method. Unlike international bank transfers at the time, it was low-cost and almost instantaneous. An added benefit for merchants (less so for users) was that it was irreversible, removing the threat of expensive charge-backs.
However, the improvement in domestic payment methods and the rapid development of alternative (non-cryptocurrency) forms of international transfers has reduced bitcoin's advantage in this area, especially given its increasing fees and frequent network bottlenecks.