A few years ago, I learned that there is no device in the world that prevent your car from being stolen!
Mine was taken at gun point [luckily, they didn't take me with them]. The fitted alarm system has the so-called "Anti-Rob" function. It works this way: When the car is stolen, press the button and it will immobilise the vehicle after about 5km.
Usually, this is a useless function because the button is on the remote, which is in the same key-ring as the keys...which are in the car!!!
However, at the time of the robbery, my remote had broken off the key ring and I used to open the car and put the remote back in my pocket. When the thieves ordered me out of the car, the remote was in my pocket.... as they drove off, I was more concerned about the safety of my [then] 3yr-old son whom they had flung out of the car and onto the tarmac...
So I rushed to pick the little boy and only remembered about the remote one hour later when I went with the cops to pick the car from some back-street in industrial area where it had been abandoned.
Therefore; I look at anti-theft devices from a monetary point of view. How does the cost of fitting it compare with the insurance excess that I would save if the car was stolen?
I then only fit the device whose cost is less than the saved Excess.
So; why spend 30k on a device that will save me the same amount of Excess as a 5k alarm system?
Nothing is real unless it can be named; nothing has value unless it can be sold; money is worthless unless you spend it.