Decks With This Card Recent public and tournament decks using Gungnir, Dragon of the Ice Barrier
Oricorio is a single card solution to entire deck archetypes
Its possible a vacuum may open in the market, and scared resellers will try to dump packs for less than they paid
Metalcrunch is a level 9 monster with 2800 ATK...but it can normal summon itself if the player controls no monsters
Honestly, this is true for all difficult decks to play, and for all players (I am on week 2 of trying to learn to play Leviathan optimally even though it quickly became one of my favorite decks and taught me worlds about water control as a whole for other archtypes)
In the end, however, each is pivotal to furthering their entire genre, and very few maintain the power and influence of these two living legends