Ofc they are not unique. But they grow with sentience(or level of self awareness - lucidity), memory storage (identity - knowing ones different build-up and uniqueness through detailed information), intellect (or thought engine - analyzer capabilities of the stored information) and emotions(^^')(subjectivity and quality of life
). Animals have basic forms of these traits that are upgraded in humans characteristics. And every one of them has it's own importance. That doesn't mean they are unique as you say, just more or less developed, animals could develop them too given enough time. Aliens if they exist probably have them hyper enhanced long time since. And they most certainly can be chemically manipulated with drugs for enhancing memory storage, emotions, even a bit the intellect. Maybe even the sentience, or more rather not enhance it but keep it steady for a longer period of time = caffeine!
If there will ever be invented one for enhancing it not deminquish it like most nowadays do, I would sign up for it immediately. That's why I sleep as much as I can, because the more rested you are, the more lucidity you have therefore the more you appreciate everything in life. People who wrongly thing if they sleep less they live more (sleep when your dead - motto) actually lose more, because they are not sentient enough most of the day to really SEE things, as they are less sentient, there is less of them there to spot everything there is = they lose more.
(With other words, if you are tired, you can read 10 pages of something and not understand 50% of the information = having less fun doing it, sometimes even feel like a torture of sorts; but if you are completely rested even one page of something can make you feel nearly ecstatic, being of more use to you then the 10 pages read while tired. Less time spent much better!
So I always say, it's not about the amount of time doing something or being awake, but the quality of it
Don't wake up at 6 a.m., wake at 12!(If you can afford it ofc) Why torture yourself 18 hours a day rather than enjoying everything for 12!?
Because it's custom? FUCK CUSTOM, it's the enemy of true freedom, embrace your own way to be, whatever it might be!