People build houses to protect ourselves and our stuff from the elements (and other climate control reasons), for privacy, for security, that sort of stuff. They are necessary for high-density living (plumbing helps to keep poop away).

Generally though, I would expect camping to be healthier than a hotel room. Hotel rooms and airbnbs are places that many humans go through, and humans are generally the main carriers of human pathogens. The only germs on your camping gear are your own ones.