My cats had no problem getting used to the litter box being inside. The inside measurements are about an inch smaller than the overall measurements, so you might need to buy a new litter box if you were basing it on the overall. I can fit a hooded oval litter box inside (just for reference). I wouldn't recommend sitting on top of it as an everyday bench, but it will stand up to occasional sitting of a person on top. I think it's better suited as a place for your feline to eat or sleep.