The only reason for region-locking, and even further, restricting sales to a particular region, is money. It always comes down to money. Fact: different currencies have different values. In China, a player can subscribe to WoW for $1 per month. In the West it's $10 (or thereabouts).
In poor countries where incomes are low, a console game simply will not sell for $60, which could be 20% of someone's monthly income. Hence region protection. By preventing casuals from importing/copying them, they will gain more sales in richer countries. If I could buy all my games at US prices, I'd be laughing, and our Autralian cousins would find themselves paying less than half what they're currently forced to.
In an interesting twist, it's pirates again who have the last laugh. Paying customers have to put up with copy protection, regional restrictions and different worldwide release dates, while the less scrupulous among us will be playing on launch day (or sooner) once any version of the game gets released without region restrictions, Origin requirements, DRM or different international release dates.
