I’m unsure if the title is phrased sufficiently and so i’ll try to explain;
(As a side note I am very much an advocate for cryptocurrency use and the ideation behind it however i recently thought of this and cant think of a sufficient answer myself)
As the supply of bitcoin available decreases and the block rewards decrease, this would generally increase the price of BTC, even more so if the demand increased.
Now assume that a country was to use BTC as it’s native currency, demand would increase while the supply remains unchanged – this would cause the price to increase.
If anyone in this country was to take out a loan that is BTC denominated (as it is now the country’s native currency), as the value of BTC increases the debt owed increases and so the wealth gap between the rich, who have no need for loans, and the poor, who rely on loans, increases.
This doesn’t seem to be a viable option, especially considering the huge role debt plays in the economies of today.