Kinda yes, kinda no.
I am absolutely here for cosmetic 'stuff that makes you look cool but serves no purpose'...that's why I'm such a massive fan of transmog (which it sadly seems has been no no'd for being too 'modern' mmo). IDK where opinion lies on other cosmetics (pets, mounts, spell reskins, player housing, etc).
To pick on specifically, say levitation: If we had a cosmetic that makes your character float and/or gives your char wings, I'm all for that...but not so much a levitate spell that has zero in-game mechanics or purpose. Never said any of them needed a use in combat, but if they're mobility/exploration type spells I feel they should have a use in world exploration. I honestly I think there's already too much 'useless spell clutter' in the spell book as it is, as spells don't replace each other at rank upgrade (but that's another discussion entirely) - this is probably what makes me have an inherent dislike of the idea of putting more 'useless' roleplay spells in there though.
I think If it was added as something more akin to the wow 'toys tab', where it's just clickables that do neat things but have zero in game use, then I'd be good with it - I would just personally prefer useless/cosmetic is segregated away from useful spells/skills. If we get something like a cosmetic only 'stone of levivation' that just makes your character float visually, and serves no other purpose, that's a neat addition. Or maybe even a /levitate emote. I think at the core we agree on it being cool to have flavour cosmetics(spells), just differ on how we think they should be baked into the game.
Spell cosmetics would also be neat. I don't really have anything against that, but if theres a no reskinning equipment stance, I'd be surprised if we get the option to reskin spells. I'm all for this one though - I hate brute, and think it's sad the final companion is the most ugly one.