Pink Candies have generally been given to winners of Halloween events or contests, only outranked by the even more elusive Dark Candy which tends to be for the #1 top winner (kind of like the Golden Egg from Easter Egg hunts) of a specific event/contest. That said, this year saw multiple Dark Candies awarded because 5 people correctly guessed the exact number of candies in the Confectionery Crypt jars, with Pink being those who were extremely close to the correct number but not precise.
That's why I said I'd hopefully earn them someday but doubt it, because I've never won an event where one can earn a Pink Candy or Dark Candy and don't think I will. Could've earned a Pink this year because my first guess for the Confectionery Crypt was 131, which was only 1 off from the correct answer of 132, but I second guessed myself and chose 117 and wound up with a Pierrot Candy. RIP.