You have probably never seen anyone eat a banana peel because we are used to eat only the inside of a banana, and throw the peel. However, in India people eat banana peels for years and it is quite normal.
Unlike the inside of the banana, the crust is firm and slightly bitter, so it is clear why they are not eating it. But there are very important nutrient in the bark and that is why you do not have to throw it away.
Banana peel is rich with B6 and B12 vitamins as well as magnesium and potassium. The inside of the banana contains these elements, but they are in significantly lesser amount.
Here is how much nutrients contains a banana in terms of the daily needs of our body:
~ 8% of the daily requirement for magnesium, which is important for regulating glucose and blood pressure
~12% of the daily requirement for potassium, which is associated with the development of new cells in the entire organism
~17% of the daily requirement of fiber, which facilitates digestion and reduces the risk of diabetes
~ 20% of the daily requirement for Vitamin B6 which helps the body to turn food into energy.
If the banana is ripe, its peel is thinner and softer. Ripe banana peel will also become sweet, so it is easier to chew and digest. If that is not enough, it can also be boiled or baked.