It's designed primarily for children with a very limited diet, and low calorie intake, and usually taken under recommendation of a dietician or hcp. There is also a drink with less calories and fat that can be given alongside a limited diet, where there are no weight concerns.
I agree. It should definately be something recommended by a HCP. Used wrongly it could probably make a child ill. Or make the situation worse as they rely to heavily on the drink and child becomes even less interested in food.