There are two main reasons why you should think about cosmetic car insurance policies: protecting your no claims bonus, and covering repairs that would otherwise cost less than your excess.
When your car suffers a minor scratch or other kind of surface-level damage, you're faced with a tricky decision: You can make a claim with your car insurance provider and have them pay for the repairs but risk losing your no claims bonus, or you can fork our for the cosmetic repair yourself.
Cosmetic insurance solves this problem. Since it functions as an add-on, or a separate policy altogether, you can make a claim on a cosmetic policy to cover minor repairs without affecting your no claims.
Moreover, in some cases, the cost of your repairs will be lower than your voluntary excess. If your repairs cost £150, but your excess is set at £300, even if you make a claim you'll still be paying for the repairs yourself. Again, a cosmetic or scratch and dent insurance policy will help here, since the excess on such policies is usually closer to £10.