Growth hormone therapy is not what you think. It is NOT all about linear growth. We are not doing this just to make our son taller. We are doing this because growth hormone plays an important role in other functions of our body too. Yes a child may grow a couple inches on GHT but that doesn't show what has happened on the inside where the heart and lungs have become stronger and more efficient, so the child can breathe better. Growth hormone is the key to all cell growth and reproduction. You can find more information on this here.
If you were to think about it as though your child is not producing enough growth hormones or the hormones they are producing are inadequate what other cells in their little body are not growing as they should? So not only is the child short, but he may have other problems too. Lung issues, heart issues, bowel issues, you name it can all be affected by not having enough growth hormone.
It is no different than giving a child who is diabetic insulin because they can't produce it on their own. You would not think twice about whether or not to give the child insulin. Why should a parent of a child who is GHD or GH insufficient have to second guess themselves for giving their children something their body needs?