If your vehicle has keyless entry, you are vulnerable to thieves being able to drive away in under 60 seconds. Keyless car theft is increasingly common, thieves use a keyless cloning and relay method, by picking up the transmission from outside your house and replicating it to the car.
The car thinks this is the original key and allows them to drive away with ease, usually without you even knowing. The Ghost Immobiliser eliminates this as an option, as without knowing the unique pin code, they will be stuck with no way to move the vehicle. Read more about this here