Talk about difference between region and langtag's region

[aphillips]

From a Slack conversation:

"preferred region" != "locale region". The region in a language tag has no relationship to the user's physical location or jurisdiction. The user's location or local region should be an ISO3166 region code (e.g. US, GB, etc.) possibly with a subregion code (when applications support such things and they were well-delineated (e.g. GB-SCT for Scotland). The user's locale, by contrast, will usually contain a region code, e.g. en-US or en-GB or en-CA which only refers to I18N API settings (such as localization of resources or formatting of numbers/dates/etc.). The region code in the locale can frequently be "in conflict" or at least "out of alignment" with the user's location.

Also, note that some locales contain regions that are Not That Useful in terms of locations. es-419 (Latin American Spanish), en-001 (International English, 001 is the code for "world")