Remittances, like Western Union, just take a few minutes but have higher fees. Especially for smaller amounts.
International bank transfers cost between USD 11 up to USD 40. Both the sender and receiver pay. They are only worth for larger amounts, for example between El Salvador and the U.S, if the transfers are done before noon and during a working day, they usually arrive on the same day.
Depositing U.S. checks in El Salvador banks is free or cost less than USD 5. This is very slow though, and may up to 30 working days to clear. It may be faster now, but it depends on the bank.
Personally I'm still not sure that Bitcoins and Western Union should be part of the solution. It seems "simple" for a country to just cap feed and ensure that everyone have access to banks.
In El Salvador simplified bank accounts require no minimum deposit, can send and receive instant bank transfers to other banks, and some allow the account holder to receive a remittance from the US just by typing remittance ID and amount.
No need to go to the bank either. They can be opened from a website or app with a selfie and a picture of both sides of the ID card.
It is also possible to receive a remittance from family using the app by filling a form with two textboxes: 1. MTCN/Remittance code and 2. Remittance amount.
Those who are under 18 cannot access this service though.
The salvadorans living in the U.S., even if they didn't enter the U.S. legally, usually have bank accounts too.
We do have the similarly named SIPA for transfers between the SICA countries (Central America and Dominican Republic) Unfortunately SIPA is not that widespread. It costs about $7.
If both ends of the transaction have bank accounts, and the sending end has internet banking (should be pretty universal even for expats in the EU at least, unsure about North America and elsewhere) then using Western Union seems like a complete ripoff.