This is no longer correct. 'Unique place' is not an option when asked "Which of these best describes your place?" There are 31 options: House, Apartment, Barn, Bed & Breakfast, Boat, Cabin, Camper/RV, Casa particular, Castle, Cave, Container, Cycladic home, Dammuso, Dome, Earth home, Farm, Guesthouse, Hotel, Houseboat, Kezhan, Minsu, Riad, Ryokan, Shepherd's Hut, Tent, Tiny Home, Tower, Treehouse, Trullo, Windmill, Yurt. (spellcheck does not even recognize five of these) However, there is no "Unique space" option - unless "Casa particular" is AirBnB being cute, which is not at all helpful to us hosts.
Those wanting to rent out an RV site with water and electric - which certainly must be a more common occurrence than at least half of these choices - are unsupported in this interface design. Compromises will need to be made, and guests searching may to make the same assumptions as the host did. Why this is a guessing game for hosts is beyond me.