Charizard is regularly cited as one of the franchise's most popular Pokmon, and so a combination of nostalgia, popularity, and the feedback loop of a card selling for a large amount prompting others to also sell theirs for a lot are to blame for the massive value
This will essentially protect his allies from one of the most conventional forms of damage and eventual banishment, being challenged by an opposing character
Known for its vibrant flame-driven design, Charcadet embodies the spirit of fire, both in its aesthetics and its battling prowess
Additionally, it carries a massive 190 HP pool that would be hard to reduce even for some of the strongest Pokemon in the game
From the same year, a 1999 Pokemon base unlimited Charizard holographic trading card blew past its $300/500 estimate to sell for $5,000
You can find those decklists here