I don't know why Bitcoin today is something people want to use, since you can send Western Union or use other payment methods (like Wise) to almost all countries.
I lived in Vietnam for a while; there is lots of WU for people abroad sending money there, but it’s really hard to send money out.
But in the end expats usually just swapped the cash with each other and sent the money in Revolut. That worked (for small amounts anyway)
Which doesn't has anything to do with the fact that if you've got Bitcoins in a village in some random developing country, you need to find somebody that's willing to give you local banknotes. That person is usually going to charge more commission than Western Union for the privilege of doing so, because they can.
The country switched to using BTC as legal tender because it was already being used as local currency because the people were using it for payments due to the lower fees.
> That person is usually going to charge more commission than Western Union for the privilege of doing so, because they can.
It seems like you're assuming this to be the case without having any real knowledge of the situation. BTC was adopted by El Salvadorans exactly because they were able to spend less on fees over the competition.