Just me but I find those tubs to be to small to begin with. Its bad enough we keep them in an encloseure let alone not give them enough room to move around. To me that dish takes up way to much room that could be used for more Leo space.
I use those food/water bowls too! I haven't had a single escaped mealworm that I know of, but superworms did find their way out eventually. But my female doesn't like superworms much so I've switched back to mealworms since