While Rare Candy increases the level of a Pokmon in the base Pokmon games, it serves as an evolutionary item of sorts in the Pokmon TCG
It all stems back from the very first set, the Base Set, originally printed in English in 1999 - the big red lizard had the most hit points (HP) at 120, making it the toughest Pocket Monster to take down, the highest damaging attack (Fire Spin for a whopping 100 damage) making it the hardest hitting Pokmon without a drawback (were looking at you Chansey with your Double-Edge attack) and had the best resistance, it resisted fighting types by 30 damage, it also has an alluring and unique Pokmon Power which essentially meant any deck could run a Charizard, if you had one
I could only have two colours, so I went with Amethyst and Steel
Then if you're the monarch, Court of Embereth deals X damage to each opponent, where X is the number of creatures you control
How Are Pokmon Cards Made