I think it will be intresting to talk about that:
All MyCard points redeemed via your MyCard Membership account can be converted to your WoW account, in values of 150 for an hourly subscription or 450 for a monthly subscription.
150 MyCard points can be directly reloaded into WoW for an hourly subscription.
450 MyCard points can be directly reloaded into WoW for a monthly subscription. 350 or 400 MyCard points can only be redeemed via your MyCard Membership account.
I bougth 350 points card, and it sems the process is diferent than 150 and 450 points card. The 350/400 points cards couldn't be reload directly by wow taiwan website using mycard option.
It sems we have to create MyCards membership account.
Trying to do that at that time, but... If someone did that already