BrowserEngineKit was originally announced with a location restriction preventing browser developers from testing their own engines on devices located outside the EU. This restriction was lifted for local development and testing as part of 18.2 beta, but it still exists for web developers.
This matters because many web developers located outside the EU support users within the EU. If they are unable to test their sites within alternative browser engines they will not be able to reproduce user issues and ensure their sites work well across engines on the platform.
This restriction would ultimately lead to a worse experience for end users, and would disadvantage alternative browsers on the platform. Web developers should be offered a mechanism to easily test in alternative browser engines regardless of their location.