It's aimed at youngsters who really only want to get on the road and be legal so it would lower their premium and in most case the insurer would only have to cover third party damage.
The main obstacle to new drivers is the cost of insurance, you can buy and old banger for �1000 and have to pay more than that to insure it. In most cases this is effectively third party only. There is of course a large risk based on what they might hit. So if young snotty stuffs it into a Bentley then the insurers have done their money!