I think making bitcoin a national reserve is different from making bitcoin an alternative currency/payment method. Governments are looking to use bitcoin as an asset class more like gold than a currency. Also, using bitcoin as a currency or payment method would be a very different matter as it could impact country's currency, unlike using it as a national reserve. And I don't think governments would like that.
Basically governments don't like Bitcoin and don't want to make it as their national reserves, because it affects their fiat currencies or CBDCs. It can be a snowball with small countries want to try like El Salvador, Bhutan, then several big countries want to try. After several years, the snowball starts with many countries and it becomes unstoppable, irreversible.
Not to mention, will people actually be interested and accept using bitcoin as a payment method? From what is going on, it is easy to see that most people just want to accumulate as much as possible and hope to get rich from it. No one wants to spend their bitcoins and many consider it a waste. I am not optimistic about the idea of using bitcoin as an alternative payment method.
A payment method is only one of many use cases for Bitcoin. People can use Bitcoin with many use cases and they don't need to use their bitcoin in a same way. If they can access their bitcoin, make a transaction and there are miners to confirm it, there are many types of deal with Bitcoin as a middle mean to compete those deals financially.
The bullish case for Bitcoin is a book, with insightful information on Bitcoin, fundamentals to different bullish scenarios for it in future.