While -X loyalty costs existed since Lorwyn , Gideon, Champion of Justice was the first planeswalker to have essentially a variable positive loyalty ability where he could gain a different amount of loyalty depending on how many creatures the opponent controls
In fact, Blue-Eyes White Dragon is the strongest normal monster card in both the Yu-Gi-Oh anime and card came
White has gotten more blink support in recent years, with Ephemerate finding its way into more and more decks as a value play
Even in a set with a dedicated self-mill archetype, a 2/2 like this is far too fragile to expect to be your win condition
Normally "Hourglass of Courage" has to be face-up on the field for 3 full turns for its double ATK/DEF effect to work, but if "Call Of The Haunted" is used to revive it during the opponent's turn, its effect is applied on the player's next turn, even though this is only the second turn
It has helped to establish them as one of the most popular brands of trading cards