Cats are odd creatures. Every species has its quirks, of course, but I'm sure that cats have more of them than other animals. They seem, for instance, to be boneless, and able to sleep or rest in any position.
My big boy Renn loves his cylinder-house cat-tree. He spends much of his time there, and, except for night, when he sleeps on the bed, he snoozes almost exclusively in the cylinder. He will rest with his head at a right angle to his body. That would leave a human with a permanent twist to the neck. But Renn finds it comfy.
Then there is this pose. Renn will hang his head like this for five, ten, fifteen minutes. He may be studying the floor, noting the difference between rug and carpet, carpet and linoleum; he may be pondering the fabric of the cat-tree; he may be thinking about existence.
Or he may enjoy the feeling of blood rushing to his head.
In any case, it appears to do him no harm. He spends a certain amount of time lolling his head over the side of the cylinder and then pulls it in. Enough thinking for now; time for a nap. Right, you lazy dog?