There's many more points on the gradient, some of which are of practical importance. A person in deep sleep is less conscious than someone in light sleep who is

There's many more points on the gradient, some of which are of practical importance. A person in deep sleep is less conscious than someone in light sleep who is less conscious than someone blearily waking up who is less conscious than that person when they're wide awake. More practically speaking it is medically and ethically important for a person under anesthesia to have low consciousness.