This happens through: Sets going out of print : When the Pokemon Company stops printing a set, sealed product and singles become scarcer over time Cards being graded : Every card sent to PSA or BGS is effectively removed from circulation, reducing available supply Cards being lost or damaged : Over decades, vintage cards are gradually destroyed through wear, water damage, and disposal Collector vaulting : When collectors buy cards to hold long-term, they remove them from the market 4
On summon, it can grab a Link monster from grave and equip it to gain "Borrel Counters" equal to that monster's link rating
Finally, the deck aims to put tons of cards into your graveyard, and then take advantage of this (for example with Izoni, Thousand-Eyed, Golgari Grave-Troll, Jarad, Golgari Litch Lord, etc)
But, the sparkles are nice as a starting point in any case