Kitten VIN numbers ?

Both Jarama and Urraco have a small chip in their backs, that give them a VIN number kind of thing. Just wondering how widely used this system is in shelters, so that I know the chances of them being discovered if lost and brought to one ? Was it a minimal attempt ? Or will this actually give them a better chance of being returned ?

It definitely increases their chances of being found, however, not all vet offices, or animal shelters have the necessary scanner needed for the job. All my cats are microchipped except the new kittens.