I figured it out right after making the thread. And it's partly because I want to see what kind of latency I get over there from the US and I have a feeling I may be able to actually find some better raid schedules over there than in the US because I have a very weird schedule.
I'm only getting max of ~100ms latency on EU servers (only tested The Maelstrom currently).
Previously EU and US had separate keys, but ever since battle.net was introduced I'm not sure. Either way: if you try to add it to your US account you will get an US wow account. You need EU account to be able to play on european servers, regardless of what kind of key you get.