If the milled card is a spell, the player can use the effect of the card without paying its costs on the next turn
But already in 2017, many yugioh players paid attention to the card, as it became useful after the release of support for dinosaurs
Admittedly, of the builds I talked about here, the only one you're going to want to play at a big tournament is Dragonsworn because its the most consistent and powerful by far
Of course, GY is also an important resource, but as an effect of a high-level monster with summoning sickness, it's pretty dreary
After they are destroyed, rather than going to the Graveyard, they go to the Spell and Trap zone instead, the first Archetype based around this
Elemental HERO Dark Neos X DARK Level 7 [ Warrior / FusionEffect ] ATK 2500 DEF 2000 "Elemental HERO Neos" + "Neo-Spacian Dark Panther" Must first be Special Summoned (from your Extra Deck) by shuffling the above cards you control into the Deck