Sprouts are highly concentrated nutritional powerhouses. Whatever makes the mature plant good, there’s more in the sprouts. For example broccoli sprouts have 230 times more sulfame per ounce than a head of broccoli. That’s the anti-oxidant that makes broccoli so good for you.
The macro- and micro- nutrients are also more bio-available. The baby plant in a sprout releases enzymes it uses to convert all the nutrients in the seed into things it can use to grow. Proteins are more digestible. Vitamins more absorbable. And they taste really amazing!