Making homes visitable by those not living in the home is a very generous thing for property owners to provide. It tells anyone not living in the home that they are welcome as soon as they get close enough to enter.
Neighbors, invited guests, friends, and visiting relatives who live elsewhere - as well as anyone who decides to call upon a particular home - will immediately see when they approach the front door that their are no physical barriers to entering the homes. People are welcome regardless of any physical limitations that they might have.
Visitablity in its purest sense means the elimination of steps leading up to the home. Even if there are just a couple of minimal steps to overcome, the home still might be accessible and thus visitable. The idea is that people should not be discouraged or made to feel unwelcome because of any physical challenges presented in getting to the front door.
Once at the door, the easy path into the home should continue. The entrance door should be directly approachable and accessible - easy for anyone to move through and enter the home.
Inside the home, the flooring should be hard surface - hardwood, laminate, engineered wood, ceramic or porcelain tile, vinyl tile or linoleum, terrazzo, polished concrete, travertine or marble, slate, brick or terra cotta, or similar materials. It should provide good support for getting inside the home and moving about within the public areas of the home (foyer, living room or great room, hall bathroom or powder room, dining room, kitchen, and family room).
Passageways should be sufficiently well lit and wide enough to provide safety and comfort for anyone moving down hallways or entering other rooms through doorways, cased openings, or archways.
Focusing on making homes more visitable would immensely improve access to them, their inherent value, and marketability (resale potential) as well as making them more comfortable and enjoyable for the residents of those homes.