The benefits of silicone include:

Regardless of how many (or how few) miles you have on your vehicle, regularly scheduled oil changes are critical for keeping your car running newer, longer. When you head in for your next oil change at a nearby Firestone Complete Auto Care, ask your technician about a high mileage oil change, especially if you’ve observed oil stains in your driveway or heard engine rattling. A high mileage oil change could help your car hit its next big milestone!
Start the engine and check for oil leaks round the sump flange. Stop the engine and tighten the mountings.

In this an auxiliary lip is provided along with the regular sealing lip. The additional dust lip protects the main sealing lip against dust and other fine solid contaminants and therefore this type is recommended for use in polluted environments. To achieve a long lifetime a suitable lubricant between the two sealing lips should be applied.
Jiri George Drobny, in Fluoroelastomers Handbook (Second Edition), 2016