I know very little about them in general since I haven't been able to purchase any yet. I do know that according to every nutritional chart I have found they are the most well rounded insect to feed beardies. They have the most protein, plenty of moisture and calcium and no hard outter shell. In other words they would make the best staple especially for a growing beardie. As far as the moths, I'm pretty sure dragons can eat them as well. I don't know any thing about their nutritional content however
Yep, I know of some beardie breeders who claim they give silkworms as the sole feeder insect for very young hatchlings and claim they get a great headstart from this diet cf with woodies or crickets.
BSF maggots are near impossible to buy as feeder insects here in Australia and I expect if they were available commercially these would the feeder of choice.
I gave George and Mildred (BTS), then Puff and Rex ,and more recently Peppa and Toothless, small silkworms as one their 3 daily insect meal when very young (up to 4 months old) and as they and the worms grew, it become medium silkworms as one of their two daily insect meals up to about 6 months old at which point I ran out of silkworms.
I tend to give a mixture of staple high quality live insects to my lizards when they are young and growing fast. Silkworms are great as a feeder insect - I essentially left the worms on a bit of fresh mulberry leaf in their feeder bowls - the worms don't move fast of far.