The main reason why cats wash so actively and often is to stimulate glands that secrete a special secret. It further protects the coat from moisture and sudden temperature changes. By purring and washing, cats express their social activity. It happens that cats living together lick each other like mothers do with their kittens. This is how they express their affection for each other.
By the way, mother cats lick their kittens regularly. It is done not so much for the love of cleanliness as for the purpose of body massage and stimulation of breathing.
In addition, sometimes the cat can wash its hair if it is terribly upset about something. Brushing the coat helps Murka avoid stress - animals have it too. There is even such a theory, as if the cat’s body temperature rises when stressed, after which they start washing to lower it.
As you can see, there are plenty of reasons for cats to wash in the morning and during the day. It is not always connected with the well-known sign of “calling” guests.