One, we wanted a crew member from the blue part of the color pie and two, we wanted a Wizard
Vampire Domination lets you negate and destroy any effect activation, Vampires Domain gives you more Normal Summons and LP draining, and Vampires Desire can swap out monsters on your field for Vampires in your GY, or setup your GY with other Vampire monsters
There are a few slots in every weenie deck for non-creature cards like Basri because white has no haste access so playing a pump spell is your only way to get extra damage right away and speed up your clock by that critical turn
As an added bonus you can bring back a Alucard as well, which you think you be bad, but Alucard will still add a card back from your grave to the hand when he dies and still protects your other monsters from attacks, and you can summon a Downerd on top of him if necessary anyways
Mystery boosters are designed more for fun and enjoyment than the more cutthroat supplement sets like Ultimate Masters (which, while awesome, was defined by a high price point the and drive to win a pod to get the Box Topper)