Sal Khan did an interview at the Commonwealth Club this past week where he stated that the reason for region locking is one of availability and cost. It seems like MSFT is only footing the bill for US use, rather than for the world, so there's still the matter of figuring out how to further reduce costs to make it cheap enough to give away everywhere.
I'm not sure why that implies that the paid plan is not available outside of the US.
I agree with both of these takes but want to add that the tool might not have been tested on all the languages spoken outside of the US. Can't be too careful with kids in the target audience.
I'm not sure why that implies that the paid plan is not available outside of the US.