Even if they do eat them they are worthless because you can't gutload dead mealworms. There's no nutrition in them. But in reality, leopard geckos are not going to eat dead prey.
This.
Its like a mcdonalds diet compared to one full of fresh grains and veggies. Should be a no brainer.
Google "breeding mealworms" to find cheap ways to keep mealworms alive and full of nutrition for your gecko. It is beyond simple to keep those guys arrive and full of nutrition.