The Gold Insurance doesn't cover damages to the chassis of the vehicle, damages to tires/wheels, water damages, damages to the engine, radiator or transmission, towing fee and damages done by animals. The Platinum Insurance covers all those damages with 0 ISK deductible/self-risk.
The Platinum Insurance Package is the best insurance plan any car rental company in Iceland offers. It basically covers everything with 0 ISK deductible/self-risk. It even covers water damages and damages to the engine and transmission that no regular car rental insurance covers.
The Platinum package also significantly reduces your liability should you require a tow truck, with a small deductible of 35.000 ISK. Without towing cost cover, you could be liable to cover the entire charge which can be as high as 600.000 ISK.