A varied diet is always going to be healthier, especially in the long run. With the exception of animals like pandas or koalas, relatively few species feed exclusively on a single food item their entire lives. Different feeders will supply your reptile with different vitamins/nutrients and in different ratios, which help to fill in gaps. For example, crickets have about 3 times more vitamin C in them naturally than mealworms do. Butterworms have a significant amount more calcium than mealworms, as another example. So by sticking to a single feeder you have to work more diligently when gutloading and supplementing, and most people don't really put that much effort into gutloading.Why do you think this? That is true about wax worms but not mealworms.. many of us feed just mealworms as a staple.