Buckwheat contains essential nutrients: proteins, fats, carbohydrates, as well as calcium, phosphorus, iodine, and vitamins B1 and B2, PP (rutin, which, by the way, is industrially extracted from this grain).
You won't be able to confidently claim that the byproducts of the human body don't possess valuable taste qualities until you've thoroughly tried them, right?
Except the ones we've made