Magic: The Gathering cards can lose financial value for several reasons. Firstly, reprints of highly sought-after cards in new sets can flood the market, increasing supply and diminishing the card's rarity. Secondly, shifts in the game's metagame and card bans can render once-valuable cards less desirable for competitive play, affecting their market demand. Lastly, card rotation in formats like Standard can cause cards to lose value as they become ineligible for tournament play, leading to decreased demand among players.