Christmas horses give a gift once a month on the 25th. They always give 200 passes on december 25th and the other months you get 1 of the 3 prizes they offer at random. You can see what gifts they offer either on the Special Horses page under Achievements or by clicking on the little half sun icon on the divine's page. Only you can decide if this is worth it to you. It would take 8 years to get the pass value back from it if you do not value the other gifts.