Oder is actually free molecules of something in the air. Although it is invisible, it is a physical thing, and most animals have far better noses than humans. In fact, scents and oders are very important. They know a big potentially dangerous animal is right outside the door. To me, this would make me feel perpetually traumatized. I would think that a litter box nearby might either bother them, or be an actual pollution problem that could cause a medical issue. Further, the purfumes and scents in some cat litter are also a pollution issue that might interfere with their breathing or quality of life. Since I would not place the bed of an infant human right next to a cat litter tray on the basis of the same potential health or quality of life issues, I would also not place the cage of an animal there. A cage forces them to be where they may not want to be. As the human, I am responsible that the cage, the surroundings, the furnishings are all sanitary, and good for my little pets.