Other countries should use see El Salvador that invested in it and adopted it for transactions as an example of how Bitcoin could affect an economy positively. It's helped them to improve their enocomy by reducing the rate on inflation in their country, though it didn't occur as fastly as speculated, but in the bull season when the halfing fully comes as speculated their economy could become very robust, since it's adopted over there.
El Salvador is a country with a relatively small territory, so managing it is not as complicated as countries with large territories, various beaches, islands, etc. This also needs to be considered because to withdraw the total fiat currency and implement new payment options there needs to be a big meeting, a joint agreement, have a target far in advance and I think the process is not an easy one.