Before we can always see countries decline the idea from investing on Bitcoin its because some of those countries call it as scam, volatile risk and afraid of global pressure brought up by some institutions like IMF that threaten them that they can't borrow money if they would engage to invest on Bitcoin.
El Salvador stand firm on what they believe is right for them. That's why right now they manage to earn good results together with gaining global recognition to lots of country on the world that looking after on their Bitcoin adoption made.
El Salvador would provably gain more success if Bitcoin will succeed to gather more global support and demands.
Yes many countries especially poorer ones first said no to Bitcoin because they were afraid IMF who might have stopped lending them money. El Salvador however bravely decided to use Bitcoin as official money. This was strong statement that they wanted to control their own finances ignoring global pressure.
Now that they are seeing good results and other countries are paying attention it shows that their big risk is starting to work out. If Bitcoin continues to get more popular and stable around world El Salvador will gain much of success proving their controversial decision was smart.