Found a different page where it does indicate it, but again its pretty vague.
Welcome to the Gameforge support system.
From now on we will provide you with the chance to register an account for our support system.
An account simplifies processing of your tickets and helps us to handle your requests more efficiently.
If you do not have an account for our support system yet you can register here.
Even reading this retrospectively, its still open to interpretation. I would reccommend simply adding the disclaimer that the Gameforge User account is insufficient for creating Support Tickets.