>>40304441The hat, the green-colored mustache and beard, and the comical trope of how leprechauns are often given a pipe to smoke. Galarian Weezing smokes poisonous air and releases purified air.
Leprechauns are fairies. Unicorns are not. Unicorns are just horses that use magic in their horns to remove poison from water sources and food. Magic is associated with Psychic-type. Unicorns only have a weak association with fairies at best, as they are both mythological creatures that appeal to little girls mostly and can use some sort of magical power to change their environments.
Not every mythological creature is given a Fairy-type, just those that have an association with fairies. Elves, sprites, pixies, and yes, even leprechauns.
You're the true brainlet if you think a Pokemon that is based on a fairy shouldn't be fairy-type, and that unicorns are fairies.