Comment by root9876

It will be to prevent access to third-party app stores as both the EU and Japan legislated they must be allowed.

> In a support document about alternative app marketplaces in the EU, Apple explained that “device eligibility for alternative app marketplaces is determined using on-device processing with only an indicator of eligibility sent to Apple.” In practice, iOS users in the EU who want to install alternative marketplaces will need to set the country or region of their Apple ID to an eligible country or region. Moreover, they will also need to be physically located in supported EU countries.

> In the case iOS users in the EU leave eligible regions, Apple will offer a “grace period” until apps downloaded from alternative app stores can no longer be updated. “If you’re gone for too long, you’ll lose access to some features, including installing new alternative app marketplaces. Apps you installed from alternative app marketplaces will continue to function, but they can’t be updated by the marketplace you downloaded it from,” the company explained.

https://www.thurrott.com/apple/298862/apple-adds-some-condit...

In addition to the third-party installation capability mentioned by siblings, Japan also has a regional capability for reassigning the side button to a third-party voice assistant (`com.apple.developer.side-button-access.allow`).

For Japan it might be the Felica chip.