Cooking on top of hob covers
Those covers are only for cosmetic appearance, they are not a cooking surface. It is not safe to cook with hob covers on:


If you are using a gas hob the covers could block airflow and put the flame out. Gas gushing into your kitchen is a bad thing
The metal is way too thin to handle high heat, it will probably warp when heated, perhaps enough to tip a light pan off. You don't want pans of boiling water or hot oil shifting around


Even if it was safe you wouldn't get a better cooking result as you are blocking the transfer of heat from the source to the pan. You are better off removing them before cooking.