One of the tricks R&D uses is to put multiple cards in the same card code slot as a way to say "These cards cannot both go into the set so we're trying them out." This keeps the lead designer from constantly getting comments that the cards are too close
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But there are always exceptions to the rule, such as heavily creature-focused decks that cut down on instants, or Commanders Like Codie, Vociferous Codex that prevent their player from casting permanents
While you can build around it, I doubt that particular deck is likely to be one of the best, and the drawback gets a lot worse once people side in instant speed enchantment removal to really punish you
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Main Collectable Card Games Pokemon Mega Diancie ex (Alt Full Art) - 282/217 Mega Diancie ex (Alt Full Art) - 282/217 Card Number: 282/217 Notes: Illus