The cat's very existence is art. Its movement, intuition, sense for the unseen. Actually, humans could learn a lot from cats. And all the animals, really. No indoors sandbox, no indoors climbing toys, perfectly clean diet for them and a liminal space where they're allowed to inhabit. In that case, in my opinion, it's advisable. But only if you can afford this. Cats are different creatures, they're useful indoors spiritually.