I received the answer: it works. You can buy an account in europe, pay with your european credit card, create in europe your account, and log from asia / usa , choosing american servers. My question covered all those points and they shortly answered: yes.
So, who was wondering if Anet was going to investigate this issue, it seems it's not an issue anymore. Maybe considering the exception case, and how GW1 was working , it was quite senseless.
Meh, well done, let's see on august if everything works properly as expected