Nothing, when done right. But not when "prep and cook" means minimal prep and using twice as many dishes/utensils as were really necessary, while "clean" means putting away ingredients/appliances and bringing food to the table and dealing with leftovers as well as actually cleaning. If we're talking about total time, we also have to consider who buys the groceries, who sharpens the knives, and a bunch of other things.

The point is that "it only takes ten minutes" is inaccurate in the sense that it doesn't properly represent the labor that's replaced by choosing take-out instead. It's something usually said by people who are already enjoying the privilege of having someone else do most of the work.