Why buy a pre-built deck
Black lacked versatile cheap dorks and this is the king of the bunch at present
In the Pokmon Trading Card Game, a deck is made up of exactly sixty cards, including at least one Basic Pokmon
If you want to know exactly what will be included, here is the full list of cards in the Secret Lair x Hatsune Miku: Sakura Superstar plus links to the original cards on Gatherer, the official Magic card database: 1x Shelter 1x Chandras Ignition as Mikus Spark 1x Harmonize 1x Azusa, Lost but Seeking as Miku, Lost but Singing 1x Feather, the Redeemed as Miku, the Renowned 1x Inspiring Vantage Secret Lair is a way for fans of Magic: The Gathering to buy unique alternate-art versions of their favorite cards
Like you weren't expecting this deck to really be viable, or these cards to be used for such a long time. Nagashima specifically referenced Shintaro Ito's Mega Audino-EX deck that won the 2016 Pokemon World Championships, and a deck that prominently featured a Talonflame
(Although I should note that we do push these decks to fringe levels every once in a blue moon.) Utility discard cards, on the other hand, do not necessarily promote the discard decks unto themselves (although they are used if enough resources for the discard deck exists)