So you’ve already had some food for thought about why you can’t just turn an oven higher, like burning the outside of the food, and melting the oven.

There’s a cooking aspect too. Not all food is just instantly cooked to what we want when it reaches a specific temperature.
An example would be like beef stew, or pulled pork. It is technically edible very early on in the process, but the breakdown of muscle fibers, fats, collagens etc takes time to get to the soft falling apart phase appropriate for the dish.