I don’t know if it’s the only reason, but one reason is that prices are often different in different regions for the same product, due to exchange rates - an item in a country with a weak currency sold at US prices would be unaffordable by the majority of people, for instance. If they allowed you to just choose a region and make a purchase, people would just buy from whatever region had the most preferential pricing… This used to happen all the time with Steam. So they require proof that you actually live in that region to get that region’s pricing. It’s sometimes inconvenient for legitimate use cases, but it’s the simplest way to get around the exploitative behavior.