Its the Chinese new year zodiac. They mention in the text it included in the 12 months.
Year of the Rabbit, which should start in januari 2023
Actually for 12 months getting 4 mounts is not bad.
Normally a 6 months is only 1 mount.
If you go to the subscription page its says this:
***World of Warcraft® mount from the upcoming 6-Month Offer***
This means that the next 6 months subscription is the Chinese new year: The Rabbit.