It's not clear what the point is. When someone wants to book a place, they either want privacy (entire home) or to be with a host (private or shared room). I don't see guests being too particular about getting a specific type of construction. Plus, those terms like town house apparently mean different things in different locations. While there is a big difference in price between a room in a shared house and an entire home, there is little difference in price between an apartment, townhouse, or house in the same area with a similar size. I don't think it would be very helpful to either hosts or guests, and would just have a lot of opportunity for confusion (what people in one location call a townhouse someone in another location calls a brownstone. In New York, they call a 2 story single apartment a duplex while in most places a duplex refers to 2 separate units with an attached wall. This would be way too confusing, and would not offer any benefit in terms of determining pricing.