I don't have vampires (yet).
Spellcasters are lots of fun for aesthetic purposes- the casting and dueling and potion-making just looks really cool and you can easily make a lifestyle out of it in your story if you want to. The magic realm is beautiful. Familiars and brooms are fun.
The spells and potions imho fall into two categories: "cheating at life" and "hilarious pranks". Some people like that and some don't.
@DaniRose2143 no, there is no spellcasting autonomy outside the magic realm, unless you make a club with casting spells as an activity. Even in the realm, people won't autonomously cast spells. They practice magic, duel, and experiment on the cauldrons autonomously. But if they're hungry they get food from the fridge instead of casting Delicioso, and if the toilet breaks they stand there and mop endlessly like any foolish muggle sim instead of a quick Scruberoo and Repairio.