Roasted vegetables get all caramelized and crispy on the outside, and stay soft and tender on the inside. Roasting vegetables brings out the natural sweetness in vegetables. The sweet potatoes and squash get a bit sweeter, and the red onion sweetens considerably (especially when you use coconut oil to roast it up) and it's bitter and pungent flavor dissipates. If you have picky eaters who are not fans of vegetables, try roasting some up and I bet they'll be fans!