What would happen if every country openly adopted BTC as their primary currency?

Let's assumes the market dominance remained relatively similar. With almost half of the world's wealth in BTC how would the relationship between poor countries and rich countries work? Countries with very high inflation would no longer have that element of their economy, would there be much point in individual countries using their own fiat or does there become a point where fiat is seen as completely worthless and collapses? Would corruption be reduced or increased? Would you be forced to declare all of your addresses to the government? What about seed phrases? Interested to hear your thoughts.