Coconut oil is much higher in saturated fat than olive oil and so is less healthy (very yummy though ). Is cornflour gluten-free? Might that be the reason? All white flours are just starch, basically, and so are not very healthy. Not that you need to avoid them entirely, but they aren't health-foods.
Saturated fats like coconut oil are very stable at high temperatures, so ideal for frying. It's not damaged by the high temps, so trans fats are not so readily formed. The saturated fat in plant foods (nuts mostly) is thought to be broken down more easily by the body than long-chain saturated fats found in meat. HTH