Without proper sleep, you not only feel terrible in the moment, but you are also at increased risk of:
memory loss and dementia
weight gain
depression and anxiety
high blood pressure and heart disease
I'm sure you don't need a scientific study (although there are many) to tell you that sleeping improves your health.Duh.
After a good night of sleep, you can FEEL it.
Your mood is better, your energy is stable, your skin looks better, you enjoy life so much more.