You can now add or remove currencies for each country.
If the customer now changes the country, the permitted currencies are loaded.
Example:
You sell to Germany in EUR and to Switzerland only in CHF.
If the customer now changes the country of delivery from Germany to Switzerland, the currency also changes automatically to CHF.
Or you sell to Germany in EUR, to Great Britain in EUR, GBP and USD, and to the United States only in USD.
The customer only sees EUR for the delivery country Germany, changes it to Great Britain and now sees the selection EUR, GBP and USD. If he then changes to USA, he only sees USD, the other currencies disappear from the dropdown.