The thing is, there will most prolly not be a good relationship between Bitcoin and governments, and that's basically just cause Bitcoin is decentralized and governments like to work with only centralized services that they can control either completely or to a certain extent, it's quite clear to governments of today that it's impossible for them to get a foothold on Bitcoin, thus they will rather sanction/ban/regulate it than adopt it.
Having said that, as far as a country's economy is concerned, I think there are very few ways Bitcoin can be of help, Bitcoin is money and you'll most likely need to have money in fiat to get Bitcoin or offer one service or the other to get it, it is not distributed for free, and even if many citizens of a country hold Bitcoin, I don't see how it can positively affect the economy. It's the duty of the government to provide what is necessary in order to improve their economic situation, if the government does such, then Bitcoin can only be an addition.
I do not agree with that at all. First of all you are probably talking about big nations, because "bitcoin and governments do not have a good relation" is destroyed by the fact that El Salvador literally made it a legal tender. Secondly in USA we have coinbase both being super legal and nobody says anything about it AND it got to be in the stock market as well, nobody will let an illegal company be there so it is totally legit.
In many other nations' exchanges are there and nobody says anything about it. Do you really think that exchanges are alright but coin itself is not? What is the point of the exchange if the coins are not alright? So, it is obvious that there is a good chance we are talking about something that is fine by governments. I think there are few, North Korea, china and the likes may not like it that is understandable but that's about it.