>>2289271Most of the appeal towards variant humans is partially a matter of seeking the exotic but primarily it's about the metaphors that they imply.
The actual physical differences or abilities between them have little to do with it. It's not that the succubi have wings, horns, a spade tail and blue skin or magic powers that makes them desireable, but it's what those things represent; a surrender to lust and becoming free from the social chains that we are forever tired of being bound to yet have no choice but to acknowledge as neccesary. They represent sexual freedom to indulge in our desires without restraint and that is what makes them attractive.
Elves were originally about being magical, mysterious and enchanting and somewhat alien. There is the aspect of their tie to nature as well, in the sort of naked and dancing in the forest kind of thing. In terms of more recent fantasy, they are a personification of feminine virtues (grace, elegance, beauty, soft, slender, etc.) in contrast to dwarves who personify masculine virtues.
For the animal variants, they adopt the metaphors associated with the animals. Cats represent a simple playfulness as you said, or a more predatory sense of being a hunter (like with the hungry tiger girl who prowls forward).
Rabbits are in the sense of being a shy prey; soft and gentle in personality yet also very sexually active and hungry.
For lamias it's mostly about the tongue. Also the whole wrapping around things.
Mermaids represent the sea. Beautiful and alluring, filled with endless bounty and infinite discovery yet also the death of men. It just combines that attraction with the female body.
