One of the unfortunate consequences of the global warming predicted is that many people will be forced from their home countries. If your small island country disappears because of sea level rise, you need to go somewhere else. If your country is swallowed by the desert because of continuing drought, you need to go somewhere else.
Most people estimate the number of climate refugees between 150 and 200 million until 2050 (Wikipedia).
If a country disappears completely, those who have their money stored in bitcoins will be better off than those who have it in bank deposits in that country. Long before the country completely breaks down its financial system will collapse, with the savings of its citizens in it. And real estate values will also go down strongly.
Bitcoin can help people in such a situation. If they have their wealth stored in bitcoins, they will be able to easily take it with them wherever they are migrating to.