Try thinking exactly how this would work. Foreign workers sending money to their home countries cannot switch to Bitcoin until either of the two conditions is met:

1. Bitcoins can be spent directly for goods and services in their home countries, or

2. Bitcoins can be exchanged to the local currency at the cost lower than existing fiat-transfer fees. Note, even if this condition is met, there would be a huge imbalance in the direction of trade - coins coming into the country, not going out. To balance things out, arbitrage/fiat exchange is needed, with all the old cost we are trying to avoid here.

Option 1 is the only sustainable option in thr long term, and we are nowhere close to realizing it.