The effect of "Harpie Dancer" can be utilized for reaping more benefits from "Harpies' Hunting Ground", or providing more swarming capabilities when coupled with "Divine Wind of Mist Valley"
During the opponents turn, Gumblar will discard another 2 cards, while Borreload Savage Dragon or Hot Red Dragon Archfiend Abyss would negate the last card, leaving the opponent with no plays
Sometimes your board might be fully occupied, so you cant activate this effect
Its downside is more meaningful than a Fish, but players dont care because theyre usually using this card to win the game on the spot (or, stop their opponent from doing so)
All in all, my point with Spellbooks recap is: It was the second deck in the format that had so much advantage in a sustained way
Modern Chase Cards The best modern grading targets tend to be high-demand cards featuring popular Pokmon, particularly Charizard, Pikachu, and the Eeveelutions, where theres a real premium between raw and graded