The dungeon cards wont need to be drafted or included as part of either players deck, starting alongside each player's sideboard without taking up a sideboard slot
Unfortunately, by buying fake cards, even for your own personal use, you are helping to improve the fake cards and indirectly making it easier for other, less ethical people to sell fakes to unsuspecting players
After a while, it became a staple of the tournament scene because it allows control decks to reliably kill without playing any creatures at all, turning lots of their opponents' cards useless by denying them targets
Note that these odds vary depending on the series of cards
This is because, unlike the packs you'll select afterwards, the cards you get from your very first booster pack are set depending on your choice between Charizard, Pikachu or Mewtwo
Find out with Pokemon Cards: The Unofficial Ultimate Collector's Guide