No data yet showing that it help improve the economy since country like El Salvador seems struggling since bitcoin is really unpredictable in terms of its movement. But once they experience all scenarios for sure that country can see some change on its financial system or maybe the economy might get a good boost if there's good events will occur in the market. For now lets see how their adoption go and if they fail or succeed with this action they do.
El Salvador are doing like investing in Bitcoin and it can help they increase value of their national treasury. If they succeed, it is helpful for their national treasury but not for their financial system.
Their financial system only can be improved if they change its structure and operation. Bitcoin can not change El Salvador financial system if it is only one of assets in their national treasury.
Their nation can be richer if they succeed with Bitcoin investment but their finance will be the same if no structural things have been changed.