I think it sounds like a great idea - I'm not a 'city person', but would love to have the experience of sleeping outdoors (in a relatively safe, legal, and organized setting) in an urban area.  I know I would be exposed to the nighttime sights and sounds that many city dwellers know and love and associate with 'home'; I'm always excited about opportunities to further my understanding of other people's backgrounds and/or cultures.  Local sights and sounds might not be associated with nature, but that doesn't necessarily mean they are bad things, as they can create a unique sense of place.