Since none of my dragons will even eat the stuff, they certainly won't grow on it.
I personally feel that pellets are fine as a supplement to a normal varied diet of insects and greens and for use while away for a few days (a dish of the pellets can be left in the cage for a weekend outing, though any longer than a weekend, I recommend having a trusted friend to check on your reptiles and ensure all is well).
Some dragons love the stuff and will eat it no problems. It is formulated in what is hoped to be a healthy diet but unlike dog and cat foods, research into proper pelleted diets is in its infancy. Even dog/cat food is still far from perfect with many brands being just as bad for dogs and cats as ever.
Dragons are smart but many do not recognize standing water as 'water' as they go by instincts more than deductive reasoning. Some can be trained to drink from water bowls, some refuse to completely even if dehydrated. They do drink out of baths, or if water is dropped onto their mouths. For the most part dragons are designed to extract water from their foods, more than from pure forms. So a dry diet of pellets severely limits the amount of water they can get by their food. Pellets are maybe 10% moisture, a standard cricket is 70% or more water.
I am not saying a dragon fed exclusively on pellets that does get plenty of water is not a healthy dragon. In your situation it appears they are doing very well. But keep in mind that not all dragons will drink from standing water or a bath, thus these dragons on a pelleted diet will be dehydrated, maybe not enough to die from dehydration, but low levels of water in the body can cause many other problems that take months to show signs, even years. One such condition is Gout. This usually appears as swollen limbs and joints as crystals form at these locations which cause alot of pain in extreme cases. There was a very interesting article about this ailment in a Reptile magazine a few months back. Definitely worth looking up to read. I think it was the October issue of this year...
-----
PHLdyPayne