Your game credits do not have to be used at the place where you won them. If you have credits at one of our regions but play at another region, these credits will be used to refund you. Thus you can use your credits at any of our 6 regions of your choosing.
However: If you click the game credits account manager in one region, you only be told how much credits you have in that region. At a next version we'll make something that it sends a message to the other regions as well, so you will see them all.