If you bought a purebred cat like the Maine Coon he’d cost around one fifteenth (.067) of a bitcoin as at the date of this post. You can deal in bitcoin fractions. As the value of bitcoins rises rapidly purebred cats get cheaper. However, I don’t know of any cat breeders selling cats for bitcoins but it might happen as individuals are selling items for payment in bitcoins only. A artist in London did it when selling his paintings for instance. An another man sold his home in bitcoins.
Note: I have valued a good quality Maine Coon at $1,000. The bitcoin is worth around $15,000 at the date of this post. That will change!