One reason we decided to grow chestnuts is because they are a very nutritious nut. While higher in carbohydrates than most nuts they have many of the vitamins and minerals of their counterparts. Unlike crops that are harvested over and over, the roots of a chestnut tree grow deeper into the earth, so they can tap minerals that farm depleted soils cannot. Because chestnuts are full of carbohydrates they make great flour and can even replace the grains in beer. So they make a great alternative for those going gluten free.
For more information check out this article from Humanitas University.