Generally you need to prove that a particular person was driving the vehicle and that can be hard if you find the vehicle at its registered address 3 days later -- "You can't prove it was me driving". It's a lot easier to charge the driver if you remove them from the drivers seat.
However, it's very commonly accepted that police chasing dangerous drivers causes the criminal to drive beyond their abilities and often get into accidents that are fatal to both the criminal and bystanders.
Many jurisdictions have rules/guidelines spelling out when to abort a chase in the interests of public safety.
This GPS dart would allow them to tail the car from a distance beyond visual range so that the driver doesn't drive nearly as insanely, increasing their chances of reaching their destination in one piece, but still allow police to be close behind so that they can prove who was driving.