I personaly dont like useing superworms. My experiences with them are:
First you cant keep them in a mealworm dish they just escape and are too big. You would need a huge dish and at that point its too big for the leo. I would suggest useing tongs or a big hemostat and feed them with those. At least for me I could not contain them.
Most of my leos wont touch them. A couple of them will eat them but most ate them once and then wont eat them anymore.
I dont think they will hurt your leo if he eats them. If they are crawling around the tank and your leo is sleeping who knows. I would personaly say use tongs because its too hard to try to contain them in a feeding dish like mealworms.