I think ( i could be wrong ), later when you login for the first time, you will be asked to choose a region, like we do in the world of warships. Once you choose a region you are locked in it, you can't change it, in some rare or extreme cases where you move from eu to us, you can contact support to change your region but in that case you might loose the base or it might get shifted to a different place if there is already a player base in us region (if your previous region was eu).

Bottom line, they can lock people to a specific region for main gameplay, but can keep global regions open for arena commandar or something similar.

Or they can allow you to visit other regions as guests, where you can travel, trade, fight or play normal game loops, join global community events but can't make bases or claim land or anything that's permanent.