Auto Currency Switcher
When a customer visits your catalog, he will see prices in the currency that is actually used in his region. He doesn't need to switch manually from default currency to the preferred one. This will be done automatically.
Self-Updating GeoIP Database
This Magento 2 extension uses MaxMind GeoIP2 database. The database gets automatically updated once a day. So you can be sure that the customer location will be detected correctly.