During either player's turn, you can detach a "Charmer" Xyz material from this card: when this monster battles a monster with the same attribute as the detached monster, put that monster on the top or bottom of their deck, then inflict damage equal to it's level x 100 to your opponent
Your strongest option is going to be getting Fishbone Quill into play, as that will help you accelerate your ramping capabilities even faster
More than enough to liquidate the cards into crafting points and build 2 or 3 competitive-level decks
Both sites also mention giveaways for partakers for completing specific tasks (defeating Devimon in-game, giving proper feedback, and more)
They know what they are buying, and prefer it that way
These patterns suggest a lack of consistency and care in evaluating and selling inventory