Metal Utensils Ruin a Cast Iron Skillet

That's a myth. Cast iron is the toughest cooking pan material there is going, and unless you are intentionally gouging at the surface it's highly unlikely a fork, spatula or whisk will do anything to it. In fact, I don't see how a whisk could do much except move the contents. You are far more likely to damage the coating layer by improper washing and storage- by not recoating it after use, using a lot of soap or soaking it, or by putting it away wet. Highly acidic ingredients can also inflict damage on the coating- but nothing you can't recover with a round of seasoning coat renewal. The only time you need to be even a little delicate with a cast iron skillet is when the seasoning coat is new, and still a bit thinner than it will become in time. But again- if you season it after use, and treat it right- it's not a problem.