I have seen many reasons given by major publishers for the distribution of free content, but international currency discrepancies is a new one. Yet that's what is happening with Civilization 6, with 2K announcing a whole range of new stuff that's going to be given away free to owners of the game's Digital Deluxe edition.
The argument was basically that people in many countries outside the US were not getting value for money with the pack vs. what it was providing when you considered what they were paying. As an example, the Digital Deluxe version's RRP in the US is $US79.99 ($107.99), while in Australia it's $US89.95 ($121.43).
Discussing the move, 2K say:
It's important to us that wherever Civilization fans live around the world, that the Digital Deluxe edition provides a great value. We saw that prices with certain currencies didn't live up to the savings we're looking to deliver, and so we are excited to offer this new content at no additional charge to those who purchase, or already own, the Civilization VI Digital Deluxe edition.
That "new content" (the Digital Deluxe pack already included free access to initial post-release stuff) will be two Civ & Scenario packs released in "the coming months" that will add three more leaders to the game's roster, with the new guys coming from "Africa and Southeast Asia".