Using bitcoin as a legal tender doesn’t mean it will be the main means of payment because this two countries can never have anything other than their own currency as such it will be used as an alternative currency to their traditional currency. So even if they legalize it today that simply doesn’t translate to its usage by the citizens, the over 1 billion citizen won’t be making daily transactions on bitcoin like you put it out, as there are going to be those who will but even use it, those that will use it will actually limit its usage to transactions that favours them in terms of fees to be paid like cross boarder transactions.

Its impact is simple any adoption growth leads to demand and in turn demand leads to increase in price. So onboarding close 3 billion people is definitely a bullish news that will pump the market